For the AFR reading, somewhere around 12 at cruise and 15 at part throttle acceleration is what I wound up with using the smallest jet and biggest rod.
I just adjusted timing. When I went to 12 the idle mixture screws had no affect even at 600 RPM. I ran the screws all the way in and the car still idled normally.
At 35 degrees the car almost shuts off running a screw all the way in, starting around 700 RPM. With both screws in it shuts off, especially if I reduce the idle speed. There is about a 100 RPM increase going from 20 degrees to 35 degrees. It starts to decrease again around 40 degrees. I left it at 35 degrees timing and 700 RPM with screws about half a turn out.
I also found my throttle doesn't always return to base idle. It goes back to 720 instead of 700 sometimes. I noticed this when backing the screw out; it wouldn't back down until I pushed the throttle and then the car would stall. So I moved the throttle return spring around and the best I could get was the 20 RPM change, but I figure that's close enough.
So if I leave my timing here then I have to lock my distributor, which seems weird to me. I just don't have a concept of why it would need this much initial timing. I have a firecore distributor that's adustable so it should be easy enough to set to 0 advance. I'll have to hook up the O2 again tomorrow and see what it does.
I also put in a fuel pressure gauge and the fuel pressure is around 5 - 5.5 psig which is within the range the booklet says for the carburetor, so that shouldn't be an issue.