I took the basic facts I could find and broke them up. Overall, things don't seem terrible. But you seem to be reacting quickly and dramatically to relatively minor issues. You've had the engine for quite a while, with its various problems, but it does start, and run, and drive. You're probably very close to getting it running well, IF you can resist the urge to make major changes. You're about to spend much more money and replace a bunch of parts, because, apparently, the engine stalled a few times after it warmed up.
Your description looks like you sit watching while the engine RPM go up and down, at idle, then the engine dies. That's not much. You have an engine idle problem.
Did you set the timing or did the mechanic? Do you have vacuum advance connected? If so, is it on a parted vacuum source or direct to manifold? Have you adjusted the carbs at all, for idle performance.
If I had your problem, I would get all of my diagnostic tools connected to the engine, start it up, and wait until it warmed up and things happened. Watch the timing, fuel pressure, etc. Try to keep it running using the throttle when the idle starts to go up and down. All you have now is "it dies while I played with the radio, it dies at a stop light, and the gauges don't work very well. Even the new oil pressure senders have been known to give low readings at idle, so a view with the engine revving a bit would help. Just not much quality info to worth with.