suggestions on timing on 70 340, programmable ignition

Well I have two setups to choose from. I have not actually installed it yet on this car, but as soon as I can figure out some base timing information I will do that.

I can either use the MSD Digital Programmable 6AL-2, which is actually kind of an annoying product really... bought it but might return it.. it only retards ignition with no way to advance it, which means locking out your distributor at high advance and retarding it where needed. The other issue is that the map sensor does not read vacuum, which means that you can't get any vacuum advance... which is nice to have for part throttle driving. What I could do is keep the vacuum advance in the distributor... i suppose that would work but I shouldn't have to in my opinion.

My other option... which I am leaning heavily towards.... I just upgraded to a newer version of megasquirt on my turbo car... so I have a megasquirt EFI system which I can rig up and use just for spark... it will to a 12x12 table based on map/rpm which does read vacuum and is much more configurable... retard at high temps.. etc... It will also have the advantage of expandability if I ever choose to go full efi.

The issue with the megasquirt is that I really need some serious timing information to fill that map... including what sort of retard would I need per psi on a 6-71... being that my motor has a fairly high compression at 10.5:1. I
m using a purple shaft cam if that makes a difference.

Either way... it's controllable. Stock dizzy I think.. will need to lock it out.