If it turns out that there is a imbalance between how much primary jet it wants when cruisng at part throttle load just on the primaries and the jet size it needs for correct WOT AFR, then the primary power valve restriction size and the primary high speed air bleed will need work. This is not unusual when using a N/A carb on a blower motor.
Thats why screw in swappable metering block orrifices are desired. When a carb(s) is tuned right for a blower it is very responsive in all modes and throttle inputs. It takes some work to get there.
Great to hear of you progress.. and getting the little bugs worked out.