@SlalomSteve @dude If the ZO settings always worked as intended and every boat ran the same way with them, then yes C2 or C3 might be ideal. Unfortunately there is so much variation between boat brands, models, years, engine choice, etc. that it's never that straightforward. C2 might feel like B3 on another boat, etc.
I typically try and run a C2, as C3 can be a bit too aggressive, but often times depending on the boat and how it feels I will move to either B2-3 or A2-3. I almost never run a 1 number because it's just too slow to come on, and you need to have the boat gassing you on the way into the 1st wake.
An interesting side benefit of this technique that I've found is that the better I do it the less I seem to notice the differences in ZO settings, especially at 34mph.