Use or don't use vacuum advance on distributor???????????????????

I'm doubting I can be of any help either but your are right about battling two issues at the same time.
IMO your main problem is fuel, motors don't die after 2000 RPM on ignition issues. Float bowl fuel level, jetting port synch, something is the fuel system.
The ignition could be an issue but it is definitely secondary.
I'm out now too. Best of luck to you, it should run like a squawking monkey when you get it.