Id like to try and help you as I have had a finicky Roadster that has had many troubles at different times starting. But I am unsure of what is actually going on when it is not starting.
You said it wouldnt start after running dry. My first guess would be is that something got stuck in a line along the way. People have sent compressed air from the front lines back to the tank to clear them, but that doesnt sound like it is your issue if you indeed see fuel filling the filter.
That would be my next guess is that you have a clogged filter. You said you changed one, but double-check that there isnt a second. I run 2 filters, one before, and one after my manual pump. Did that after having to replace the pump.
If you have fuel, then check for spark, which it sounds like you have done. I have had multiple electrical issues from keeping my car starting and running. I have the El Dizzy set up. There is a small plug that connects to the distributor that has found a way on more than one time to work itself off. I also had to change my fuse box due to extreme corrosion. Also look at the wiring from your ignition switch. This was another gremlin that had to be chased away, as the switch was replaced, not wired correctly, and became finnicky afterwards. My final non-start issue was because my starter was locked up.
So without knowing more about what isnt working when you cannot get it to start, I would check those connections at the dizzy one more time.