If this is going to be driven on the street on anything like a regular basis, I'd strongly recommend you use a mechanical advance curve and not lock out the mechanical advance. If you use more than around 22-24 degrees of initial, there's no point in adding more advance at idle by using manifold vacuum- so use ported in that case.
This is going to require tailoring the curve to match the combination, so start at a safe baseline and work your way up from there. KEEP NOTES! You may think there's no way you won't remember the changes you made, but trust me- you will not remember them all.