So I did a little digging. It looks like the distributor I have (Summit SUM-850001R) has about 22 deg of mechanical timing built-in. So if I had it set before at 34 (or higher) degrees total the initial I found when I started would have been about right at 12+.
Right now I have 8 degrees initial which in theory would give me 30 degrees total. The 27 I was seeing might be that I wasn't revving it high enough, full in is between 3000 and 3500 RPM. I have to admit that I'm a bit of a chicken when it comes to revving engines w/o load.
I took it for a drive today and it didn't ping but it also felt a little lazy throttle response-wise. I think I'm going to bring it back to 34, see what it does and if it pings just take a degree or two out until it's right.
I suspect there are some underlying engine issues that might make that no-ping/best-performing window rather small.
K