Best way to tame a gacha is owl pellet. I tried structures and it was way off from being tamed according to dodorex. What I would do is get a bunch of snow owl (I have 5 surrounding a pair of gachas) and play a normal day on ark. At the end of the day just before you get off, check on your gacha. I have done this and made 200+ pellets in a few hours of playing and if you don't have a gacha and would like to tame 1 get a tame of yours with alot of weight (best an argy) and collect stone. Give the gacha 100 in a stack and feed all of it. The gacha will spend its time eating just 1 stack of 100 stones before moving to the next stack. It can also give you time to run and grab more stone if needed and don't bother about tame efficiency going down to its minimum. I tames a level 145 gacha with stone and before it hit 100% its tame efficiency was at 10% (6 levels) but at the end it gave me 40 levels once tame. Up this post if this tip was very helpful for you.