You've been given some good advice in this thread. Let me summarize for you.
You have three basic problems.
1. carb is too big for the engine.
2. wrong intake manifold
3. wrong pressure regulator
If you intend to keep the 750 carb, switch to the lighter metering rod springs which will help alleviate the over rich idle. A spacer will help but you really need to replace that manifold with a good quality dual plane high rise. A torker manifold is suited for the track but doesn't do well on the street. If you want to continue using the in tank pump get a regulator with a return line. All you're going to do now is burn up the pump, and its a pain to replace. Also running an electric water pump on the street is not the best idea... again another item best suited for the track.
Setting the idle mixture screws on an AFB is pretty simple and can be ball-parked by using the following procedure. With the engine shut off, screw the idle mixture screws all the way in (clockwise)... but DO NOT force them. Once they're all the way in, back each one out 1 1/2 turns. This should give you a basic setting. Any further adjusting should be done in very small increments while the engine is running.
"Old age and treachery will always trump youth and exuberance." - Anonymous