I forget from your earlier thread - you replaced the needle jets to stock parts, and I assume, the jet needles as well? Have you tried raising the needles 1 notch? This might also require a bit of fine tuning of the air mixture screw on the bottom of the carbs, but maybe not.
What is the aftermarket exhaust system (mfg/model)? Is it still a 2-into-2 system or 2-into-1? Crossover pipes up front and behind the centerstand, or??? Lastly, are you using stock airfilter enclosure/filter or K&N filter or the dreaded "pod filters", or ??
While I don't profess to be expert in this area, I have a little experience. IF you are not showing signs of running too lean from the inspection of new plugs put into it and run in a bit, I'd first look at raising the needle position on these carbs a notch before changing main jet size. But, that's my $.02 and is probably worth that much.
Even if the exhaust system is LESS restrictive than stock (maybe yes, maybe no) if the incoming air/fuel mixture doesn't keep up with the outflow (like a pump) then the incoming mixture is the restriction. But, if you've got the incoming air supply flow improved to keep up with the exhaust outflow but don't have enough fuel (running lean), then you've got to look into jetting changes.
What I think can throw everything into a tailspin is that some air intake filers, like the "pod filters" fitted to some of these CV carbs, result in extra airflow at lower roadspeeds, but actually have less airflow compared to the "snorkel" box of the 80s era bikes at higher speeds, resulting in the bike actually running too rich at 100 km/h where it was running lean at 20 k/h - this is where making adjustments becomes a magic balancing act that I personally try to avoid.
