High compression like that I'd set it up for 16 BTDC at idle, 30-32 total mechanical by 3200 or so rpm. Its difficult to get that right without an accurate Sun machine that has a recently calibrated tachometer.
Likely you'll need to weld about .040" in the shorter slot. Maybe a hair more.
Our race engine runs 24 at idle, 28 total. The practice motor at 11:1 is set up as I described above. Scalded cat!
the advance weight pin travels in the slot .0143" per degree of distributor advance. The distributor will advance half of what you see at the crank due to the doubling effect of the timing gear set. So for 8 degrees in the distributor, = 16 mechanical at the crank multiply that figure by 8 and weld up the difference from your slot with the weight in still in it.
So what you are saying is I basically need to fill in around 1mm to the short hole, and I do nothing to the long hole?
To me it would seem like I need to do both sides, but that is what I see in my head, I have never done anything like this before.
Is there a reason for only doing one side, does it lock it in better?