gotta ask, I aint familiar with Stromberg carbs either. But now that I see that its a 2 bbl and not a 1 bbl it should have 2 mixture screws. are they both even? By past posts in this thread it sounded like you were only messing with 1 idle mixture screw. Are both "peaked out" where the vac shows highest with each screw where its currently at? If they're off balance then that can cause issues too.
