Don’t. Just use Larimar. You can get up to around 60% (I actually think it’s 50%) GF with it. 650% Luck/Gold Find is max. 200% Item Drop is max. Unless you’re making an all out farming build (like @cronos4321 : Farming Build [Warrior] Fortune Bringer), don’t use anything but Larimar for GF and Luck. You can use Rubies for Item Drop if necessary, but save those higher up crystals for your wicked gear you’ll eventually make.
Cuzeg, you can have a different set of gear for farming. It’s not a no-no.