Fuel -- you are concentrating on this area , with lots of advice
Air - i would take it for a run without any air filter just to eliminate oxygen starvation,, but again your methods seem fine
Spark - don't assume anything here. I have spent too many hours faffing around because i assumed plugs and gap, leads, and importantly condenser or electronic ignition were all new and therefore ok. You may have to substitute for a known good working dizzy to check the electonic ignition. Good luck