MAX CPC is the one part of the setup I'd actually hang my hat on, especially when Performance Max is running riot. Had a rep push me toward Target CPA once and it absolutely nuked my conversion flow-took weeks to claw back control. that's not just a rep problem, it's a lack of accountability in your own bidding structure.
the real trick? Keep MAX CPC tight enough that it forces the algorithm to work within sensible limits, but not so low you cap out on impressions. I've found starting with your historical cost per conversion minus 20% gives a decent anchor point, then adjust weekly based on impression share data. If you see any campaign spending like it's on fire, that's your signal to drop the max bid further or switch to manual CPC for that leg.
Reps will always sell you on automated bidding because it makes their numbers look good on paper. your job is to protect your margin. Stick with MAX CPC, monitor Search Impression Share, and ignore the "helpful" suggestions until you've got at least a month of clean data.
