main and hireling characters have average experience, luck, gold, and item pick up rate, with a bonus 100% on the item pick up rate.
luck is the affix that will improve your chances of getting higher tier items like crystals, myth stones, and gear/equipment.
item drop is what increases the amount of what ever you are picking up.
when talking about the average between the main and hireling, lets look at your Fortune skill.
your hireling's Fortune skill has 50% luck, and the warrior is 72.5% luck. that is 122.5%/2 = 61.25% luck. same for gold find. the item pick up is 61.25% + 100%, I think.
experience works the same way, with the addition of, the bigger the difference between the mains and hirelings levels, there is an experience penalty based on the difference.
my advice is, if you are going to Ascend for the Perks, just focus on getting your experience to 200% for both characters, then farm for experience around levels 100-110. experience from monsters maxes out at level 100. any space left over on your gear is for defeating monsters, and any left over after that is for farming affixes.
there are a lot of posts for main/hireling builds.
I have read one person saying he didn't get any perks for his hireling, just uses it for farming. many people get the Dealer Perk for their hireling. when you sell the hirelings items, Dealer lets the hireling sell items for 1,000% of their worth.