I just bought a 2020 ZS232 and have noticed the same sensitivity to the wave but after couple days of playing with it I think I am starting to get it figured out. My current preferred set up is as follows.
Usually 5-7 people
full ballast (dealer recommended draining the small 250lb bag on opposite side, but I didn't notice a difference with this)
Center tab at 50-60 (70+ makes wave noticeably shorter but less steep and friendlier for beginners. this tab is the easiest way to mellow out wave
surf tab slightly larger number then center tab. ie center at 55 and surf at 65
I also noticed speed is huge too. dealer recommended 11.2 but my wave is better at 10.9-11. haven't played with lead yet.
I will keep you posted on any new tweaks or findings.