Justin's basic carb 101-vac secondary
Here is what you do with a vac sec carb ...
Put the stiffest spring or setting on the secondary. You don't want it to open because you want to focus on the primary and not have the secondary interfere and throw you off. Then you take it out for a cruise..who cares about the acceleration for now... you want to lean the jets till it surges 'test anywhere from 45 mph n up to 60mph' creep up in speed to again insure the sec stays closed...then once it surges a hair.. jet up 2 sizes. Check your meter if ya want. Now start dialing the pump shot for a nice smooth roll of the throttle type acceleration 'from a stop'... then go out and try stomping on it... try a power valve that's about 2" less than the idle rpm... take it out and stomp on it again. Once you get it pulling smooth till it plains out ' due to late secondary- still mostly closed with the stiff setting/spring possibly ' ...then you can try a light spring, lightest even..n see if it then bogs or likes it. Too light will bog, or can.. maybe not with a smaller size carb like you have.. but in any case.. that potential bog could throw you off course and messing with the transition when you dont need to.
Have fun.