If you have a MIG welder you can modify your current distributor to limit advance. It's a bit tougher than the new stuff, but, been done for years.
MSD distributors, I prefer, are real easy to modify, so are the newer MP ones. One issue with the MSD is they don't give you a bushing large enough to limit below about 18* mechanical, so you either have to make or buy one. The MP's I believe can get pretty low on mechanical advance with their adjustable advance stuff.
You'll like the responsiveness of the engine once your initial gets sorted out. It's night and day how snappy when set right or real close to right.
Good luck with it.
Something else that came to mind... if using a dial back timing light with the MSD, verify the reading with an old std, inductive timing light. I never use dial backs, just my choice. MSD'd have been known to freak out some dial back lights and give whacky readings. If you don't have a degreed balancer you can do a hillbilly timing tape to mark it and get timing set.