Gold Find and Luck: (Hero + Follower) / 2 + Fortunate + Shop Boost + Map Base .
Although gold find doesn't seem to be averaged ATM so this will just for luck. Also difficulty bonus does gets averaged so if you want the full 350% mythic 3 bonus, you need both characters to be set on Mythic 3 Difficulty.
Item Drops: (Hero + Follower) / 2 + Follower Bonus + Map Base + Shop Boost .
Do note that even when hirling is dead, the affixes still apply as if you still have hirling equipped even if you respawn him/her.
Efficient mythic 3 farm build without Epiphany Set
This is for those who haven't found it yet or don't use it.
Default cap for Gold find and Luck is 650% as well as Item Drops being 200%. Item drops is 300% due to follower bonus. With fortunate , the 650% turns into 850%.
GF: This means Gold Find.
ID: This means item drops
M3 Bonus: Mythic 3 difficulty bonus
350% M3 Bonus to give 350% total GF.
Now add Fortune 20 on each character This gives 50% gold find per character so in total , 100% Gold Find total given.
350%+100%= 450% total GF.
Now add 1× 225% Gold Find crystal affix on the Main Character.
450%+225%= 675% GF. You reached the Gold Find cap easily and just 25% over the 650% cap.
850% Gold Find if using Fortunate perk.
This only took hero points on both characters and just 1 Crystal Affix on Mythic 3.
350% M3 bonus for 350% total luck.
Fortune 20 on each character. These each give 50% Luck. 50%×2= 100%.
However this is averaged to : 100%÷2= 50% total Luck.
350%+50%= 400% total Luck.
Let's add 1× Crystal Affix luck per character. These each give 225% luck so 2×225% = 450%.
This is averaged to : 450%÷2= 225% total luck given. 112.5% Luck per crystal affix when averaged.
400%+225%= 625% total luck. Only needs 25% more to reach 650% luck.
Noe let's add 2 Luck nature. 1× luck nature on each character. This is 50% luck since it's 25% ×2= 50%.
However this is divided by 2 so it's actually: 50÷2= 25% Total Luck . Each luck nature adds 25÷2= 12.5%+ total Luck .
625%+25%= 650% Total Luck perfectly.
650% luck cap reached just by Fortune 20 on each character , 1× Crystal Affix slot Luck for each character and 1× Luck Nature each character.
Appears as 850% luck with fortunate.
Let's add fortune 20 per character. That's 50% item drops per character. 50×2= 100%.
However it's averaged: 100%÷2= 50% Total ID. 25% item drops per fortune 20 .
If you use Legend Item Drops:
Each 50% item drops legend affix is 25% total Item Drops given when averaged.
I recommend 3× legend ID per character. This is 300% ID given but when averaged:
300÷2= 150% Total ID.
50%+150%= 200% Total ID. Cap has been reached. With Hirling Bonus, it's 300% ID .
If you use Fortune Mythstones for Item Drops:
It's 30% item drops per mythstone but on weapons, it's 40%.
However when averaged, it's actually :
30÷2= 15% Total ID.
40%÷2= 20% Total ID .
Fortune 20 already gives 50% ID when you have fortune 20 on both characters.
Let's add 2× 40% ID per character on weapons with Fortune Mythstone.
Lets add 2× 30% ID per character with Fortune Mythstone.
Then just 1 last 30% ID Fortune Mythstone .
40+40+40+40+30+30+30+30+30= 310% ID.
Averaged: 310%÷2= 155% Total ID.
This also looks like : 20+20+20+20+15+15+15+15+15= 155% Total ID when averaged.
Since we have Fortune 20 on each character for total of 50% Item Drops.
155%+50%= 205% Item Drops. This is 5% over the cap of 200% but you reached it.
This is 300% Item drops after the 100% Item Drops Bonus using Hirling.
Efficient Mythic 3 Farm Build with Epiphany (5) on both characters
If you do use Epiphany Set (5) on both characters, this is the part for you.
The reason being that the Luck and Item Drops are averaged by 2 so Epiphany on one character would only add 12.5% increased cap instead of 25% increased cap.
To get a perfect 25% increased cap, using Epiphany (5) on both characters is the answer for farming affixes.
This only applies for farming affixes though and EXP Gain caps.
Luck and GF: 650%×1.25= 812.5%. With Fortunate, that's 1012.5% .
Item Drops: 200%×1.25= 250% . With Hirling Bonus, that's 350% .
Ok now to find the most efficient setup for Gold Find, Luck and Item Drops:
M3 Bonus gives 350% GF. Then Fortune 20 on each character for 50%×2= 100% GF. Gold Find isn't averaged in game anymore.
To get to 812.5% GF, I'd say 1× GF 225% crystal affix with 2× 75% Epic affix .
This is 450%+225%+75%+75% = 825% GF. This is 12.5% above the 812.5% cap but you reached it easily and you don't need to add any of these affixes on hirlings.
350% M3 Bonus and Fortune 20 on both characters. The fortune 20 is averaged so it is actually 50×2÷2= 50% Total Luck to be added.
350%+50%= 400% Total Luck.
Now let's add 1× crystal affix Luck on each character. 225%×2÷2= 225% Total Luck.
112.5% Luck per crystal affix ×2= 225% Total Luck when averaged.
400%+225%= 625% Total Luck.
We still need to add 187.5% more luck until cap reached to 812.5%.
Ok lets try 6× Luck Nature on each character. That's 150% Luck each . When averaged: 150%×2÷2= 150% Total Luck.
625%+150%= 775% Luck.
We still need 37.5% Luck to get to 812.5% Luck.
1× 75% Luck epic affix is 75÷2= 37.5% Total Luck given which is perfect and this epic affix can be equipped on either main character or hirling.
775%+37.5% = 812.5% Luck.
Perfect! 1012.5% Luck and Gold find when using Fortunate.
Similar requirements to before but now we have to get 250% Item Drops cap which is 350% when you use hirlings.
If you use Legend affixes
Fortune 20 on each character and 4× Legend Item Drops per character instead of 3× per character.
Fortune 20 per character: 50×2÷2= 50% Total ID.
4× Legend Item Drops per character: 50%×8÷2= 200% Total ID.
Final result: 50%+200%= 250% Cap reached already! 350% with hirling 100% bonus.
If you use Fortune Mythstone per character for Item Drops
6× Fortune Mythstone per character.
4 of those mythstones are 30% ID which is 15% when averaged and this is on each character.
2 of those mythstones on weapon give 40% ID but it's 20% per mythstone when averaged for each character.
6× Fortune Mythstones = 200% ID per character.
When averaged: 200%×2÷2= 200% Total ID.
Final Result: 50%+200%= 250% Total Item Drops.
Cap has been reached and it's 350% ID when using hirling with the ID bonus.
Set affixes and optional affix choices:
Eternalized (5): To increase the chance of finding Eternal Legends by 250%. Combined with Treasured Perk for 550% Eternal Legends find chance.
Crystalline (5): To increase the chance of finding Crystal Legends by 250% and increase Crystal Rarity by 37.5% .
Combined with Treasured Perk for 550% chance to find Crystal Legends. This is especially useful at floor 500 where tier rarity is increased by +5 (500%) or doing Legend/Eternal Maps.
Epiphany (5): To increase caps by 25% . For farm build ,use this on both characters. The hirling is the DPS oriented part of the farm build since they don't have to wear those farming set affixes.
Nadroji (5): Increases chance of finding ultra rare legends by 62.5% . These legends are only found on powerful enemies being Epic or higher rarity but this is good with the Hunter Ring or the Hunter Perk from ascension. With 1012% luck and 350% item drops , this is very good for rare legend collection.
However it's not always necessary but it does help , especially when you begin the game.
Nadroji Bonus: Increase enemy rarity by 100% . This needs 2 Nadroji set slots , one from chest or head and other from ring/amulet. This will increase the size of the bores of magic enemies and rare enemies by 100% which is basically equivalent to 100%+ Magic enemies and rare enemies on Maps. Useful if you don't have much larimar but sometimes if you want farm hirlings to deal DPS, this won't be used as much and if you get legends very easily, this isn't necessary as much.
Mythical (5): Increases Mythstone rarity by 37.5%. Useful when you are a beginner and hunting for as many Elixir Mythstone as possible as well as many other high rarity mythstones to start making good powerful builds. What's even better is that this set is found on Very Easy mode to Mythic 3 difficulty on floor 350+ or so.
However if you have so many mythstones that you don't need to farm as much, then this set doesn't have to be used.
An optional Affix you can use is Fortune 5+ as legend affix but as of now, it's not yet worth it sometimes but it is useful. Could save you an affix slot. Eternal legend with it on is however more useful.