Right now it's set to 12 degrees initial, and it has some trouble idling while in line at a drive through. I'm wondering if this is timing related, or I've got other issues to attend to. It's got plenty of get-up-and-go if I nail it from a standstill, even if it's idling rough
You are in the ball park timing at 12 with this mild cam, it should not idle ruff at all, first check other things like the manifold vacuum level at idle, cap and rotor condition, plug wires, fuel/air filters, fuel pressure condition of the carb etc. Take vacuum readings and post it, check if the HEI vacuum advance can is connected to manifold or ported vacuum, disconnect the vacuum advance can plug the hose while with a timing light on it at idle and note the difference in advance BTDC
Basically at this point you are trying to figure out why the ruff idle by eliminating possible causes, once everything checks out OK then you can proceed to tune it.
Don't worry about hurting your convertor with a little more idle speed in gear