Focus on Coins/Kill over Coins/Wave; the latter does not scale well into the mid-game.
Useful early on, but stop improving this once you move to Tier 2 farming. TheTower-win.zip
Prioritize spending Stones to sync Golden Tower (GT) with Black Hole (BH) and Death Wave (DW) for maximum coin multipliers. 2. Lab Research & Development Focus on Coins/Kill over Coins/Wave; the latter does
Target an 80% cap to ensure you can one-shot basic enemies as health scaling increases. Focus on Coins/Kill over Coins/Wave