Timing Advance Curve

I use 35-36 degrees for total advance (not including vacuum advance). I have the timing all in at 3000rpm. Depending on engine combination, it make like it a bit quicker, or maybe a bit delayed. But that'd be a good starting point. You want the engine to feel as responsive as possible, without starting to hear any pinging. You may want to play with where you set the initial timing, and see what you like best... anywhere from 7.5 to 15 degrees. Much more than that and the starter will begin to struggle. You are correct, the bushing you'll use will be your total advance minus your desired initial advance. So 35-10, for example would require a 25 degree bushing for 35 degrees of total timing, and 10 degrees initial.