I’m kinda in that predicament right now for A/B. I’ve yet to exceed the B power limits on zwiftpower (and have yet to win a B race), but I’m close.
My tri teammates goaded me into doing a couple of A races with them last Saturday and I finished the first one in 19:57 at 4.4w/kg (and came in like 50th place on zwift & 24th on zpower). If it had been 20 minutes I would have exceeded the B limits in that race.
So I think I’m just going to race A going forward. It actually motivates me to lose some weight too, where racing in B did not.
Zwift racing requires you just race the people you end up in a group with and forgetting about the people up the road. You aren’t catching them once they’re gone. If you can do this mentally, then it’s a lot of fun regardless of your overall finishing position.