Diagnosing a Potential Fuel Problem

I just thought of something; I modded my carb to bring the vacuum advance in early. If you rev yours up to 1200 and find no signal at the sparkport, then the Vcan will not help you,during the warm-up. I find more than 1200 to be annoyingly fast, but see if you can get signal at 1400. Still no signal means the Vcan will not help the warm-up on your combo. Sorry, I forgot about that.
In this case, you only have the idle-timing and the centrifugal to work with, and you can only go so far with those, before it's too much.
Your cam is pretty big. This is a case where manifold vacuum could be made to work for you.
Here is what I would try; I would route full manifold vacuum to the Vcan. But I would route it through one of those Ford thermo-valves. The thermo-valve sits in the water jacket wherever is convenient. There are two vacuum sources sent to it;namely manifold vacuum, and ported vacuum. And it has one outlet to the Vcan. When the coolant is cold it sends full manifold vacuum to the can,and the engine receives whatever boost in timing that the can is able to give. When the engine is up to temp, the thermo-switch changes to ported vacuum, and the engine receives no additional timing at idle,at all. The switch point is not adjustable, but there are several set-points to choose from. I have used these from time to time. This system works well with engines that are able to generate a good vacuum at 1200 to 1400rpm, and with Vcans that can work with whatever signal the engine is generating. So some testing has to take place to find out if it will work for you.
It would work just fine on my 367 with a 230/237/110 cam,which generates plenty of manifold vacuum in the 1200 to 1400 zone.I was going to use this system on my chokeless 750 but I don't drive it at those low temps anymore, and I bought a dash-mounted dial-back,timing device instead. It has a range of 15*, and by setting it close to the center, before base-lining the timing, I can add 7 to 10 degrees from the driver's seat,during the warm-up. This has been sufficient with the way that the current timings are interfacing.
Again, more mumbo-jumbo,I know. But when it all works, that is the BIG pay-off. When you come out of the bar at two-am, stab the throttle two times hit the key, wait 30 seconds and drive it away; that makes my day! Oh wait, I quit drinking in 94, so maybe substitute some other venue,lol.