what would be the proper way to ajust fuel mixture on my 2bbl rodchester, rebuilding carb

The only adjustment is the idle mixture, and you simply set it to give the smoothest idle. After the rebuild, install the screws and seat them, then turn them out about 2 turns each to give yourself a starting point. Once the engine is warmed up, turn one clockwise until the idle starts to stumble, then back it out slowly until you get the idle to smooth out. Repeat this with the other screw.