I think you're doing all you can do without removing carbs and doing some physical measurements of the float as it is in the closed position.
PS - I'm sure my bike is slightly off when it comes to fuel levels. Expecially when I cold- start the bike. If she starts to slow down and attempts to quit, slightly shaking the bike right to left (to right, ie sloshing fuel around in the float bowls), causes the idle to pick up. This odd characteristic has eliminated the need for multiple starts, stops, and restarts, when the bike is cold.
GBNF: 03 T100 Luc Org and Silv: 122/42 jets, TORs, 18T, UNI filter, no AI, Polaris bellmouth, Metz 880 tires, Prog. 440 shocks (105/150 springs), 11-1124 frk springs, Thrux frk caps, gaiters, MotoTwin bars, 6024 lamp, htd grips, 12v outlet.