Diagnosing a Potential Fuel Problem

I think you are gonna need a friend,lol. Someone with tools, time and expertise.
Or you are gonna need some books. Or this is gonna be a long process.

Here are the tools you are gonna need; a timing light. Preferably one with a tachometer in it, and a dial-back feature. If you are running a CDI, you will need a special lite or more tools. CDI systems do not like DB lites and lose their place. This may be what happened to your tuner. If you get a standard lite, it may work with the CDI, but then you will need to calibrate your balancer. And you will still need a tach at or near the timing lite.
Also you will need a Vacuum gauge.
These are minimum requirements to procede.
One more time, a cold engine, especially one with a big cam,like yours, wants a ton of timing during the warm up period. This has nothing to do with starting, only to keep it running. The fuel mixture needs to be very rich, and the timing needs to be almost excessive. It is the job of the choke to control the cold/warm-up mixture. It is up to you or your tuner to give the engine the timing it is craving. I think 40* at 1200 to 1400 is not excessive during the first few minutes. This requires about 16 minimum idle-timing. 6 more in the centrifugal and hopefully 18 in the Vcan. This period only needs to last a minute or so, and then you can tap the fast-idle down, at which time the vacuum advance should also drop out. Then the engine will be running on the idle timing plus whatever the centrifugal is commanding; perhaps 2 to 4. If you don't have at least close to these amounts, nothing you do will help much.I think as a minimum 30* might work.