Hey tom, you say its running better with the coil setup you have now, but are you sure it was a spark issue when it wouldn`t fire? Just a thought, have you checked your timing with a light as the rpms increase. Also you can tell if the mechanical weights are binding when off the throttle. The timing should return smoothly to the base setting every time. The timing advancing too far or staying advanced when off the gas can create pretty much what you are saying lean mix, and stumbling at high idle also a start issue. When the engine will not start have you checked with a timing light for spark while pointing at the timing marks, not sure but this might tell if the timing is still on base setting. It sounds like you have covered a lot already and maybe this is off the wall but? Hope this helps. Larry