First is a magneto cam that is actually 180 deg
I have seen some that were nearly 15 deg out.
Then the cam needs the same lift on both side as well.
Having done that you need to look at the AA unit, it must advance and retard freely with matched springs ( again very hard to find )
After that you turn to the carb
If you still can not get it to idle smoothly look closely at the cam and in particular the cam lift.
Not odd to have them all over the place.