I respect you ideas, but disagree. I think that changing out a distributer on a car for a known good one is the best way to start. I find that the search can range from gas to spark and everywhere in between, but most of the problems I find are in the distributer. I have a few that I have rebuilt and have run for a while that are known good. It has saved lots of time when I'm looking at a car and they are insisting that it is a carburetor, and I'm just as sure it isn't a fuel problem. If you change it out and the problem goes away, it will narrow your search for the problem, if it doesn't it will also let you concentrate on the others problems you might have.
I also do this with fuel. I hang a small tank on the radiator rods and bypass anything in the tank or fuel filter, or just bad gas. I also do this for the ignition, there is a bypass sold that is more of a factory hotwire, this takes the complete switch out of the equation.
Gremlins are sometimes hard to ferret out, and elimination of whole problem areas can be of great help when the symptoms are all over the place.
Strangest one lately was on the trip to Loveland an exhaust clamp came loose and the muffler fell. Tried to wire it up and pull off into a stop we were making when it fell. The car would not run. Bolted up the muffler loosely and it just barley ran. Got it tight and it ran fine.
Talked to folks at the meet, and had to face palm when I was told that the engine must be grounding through the muffler and the answer was a ground strap.
So your telling me I need to install my new muffler before I attempt to start it?