I'm still 'getting ready' to drive my car for the first time in 30 years. One of these days I will. Every so often though I fire it up, like a 16 year-old would do.
One thing I found: It doesn't run well at all when the fuel is at or below the level of the outlet pipe in the tank. Even caused me a little panic.
The key thing for me is that you say "I switched to electronic ignition and it ran worse. It continued doing that after switching back."
I say "Hmmmm!.. must be something else!", if it ran crappy with or without the electronic ignition. Make sure you're not running out of gas, at least.
For what it's worth, no amount of cleaning and adjusting the points and timing seemed to fix my car.