Help...need advice on best ignition system, carb, timing...

Single plane with your setup (stock bottom end, low compression, stock cam) is not ideal.
It would be best to get a used dual plane.
Ignition timing needs to be correct before you start screwing around with the carb.
Start by setting initial timing at 18* initial 34* total mechanical. The higher initial timing will help improve throttle response.
Single plane intakes require a bigger pump shot. Close the manual choke 1/2 way and rev the throttle. If the stumble goes away your pump shot is to small.
If your plugs are black you are way to rich. Today's fuel leaves very little color on the plugs with correct AF ratio.