Holy bejesus. That's like 200 bucks for a second event building depending on what diamond offers you have going. Is this really a good marketing strategy for Inno? In any case, on topic. Drummers were the key I was missing from my IA diamond farms. I now fully auto-battle in IA, though a few fights do sometimes require retries and can still result in heavy losses. Honestly I'm not sure how I missed it, but I'm now taking way less troop losses and it's saving me a bunch of time. All 8 farms combined I'm spending maybe 60-70 minutes a week now. Still working on acquiring TA's on 7/8 farms...it's hella expensive and hard to find on some of the newer worlds. Important caveat: I'm unsure how well drummers work in auto-battle without a fully boosted farm.