Here is the spark table for my 383 with AFR 195's and a 219/219 roller cam at 9.9:1.
Not exactly the same combo but thought it could give you and idea of what others are running. This was arrived at from a Vortec base timing curve and then data logging runs, it has not been tested on the dyno yet.
One thing that was very clear for this engine was that although it liked alot of advance under light throttle (35), when the load increased, it wanted much less. (as low as 20 deg).
I know this info won't be a direct help as you are mech/vac timing and a carb but thought I'd share anyway to give an idea of what's worked for me.