RE: I converted a glow engine to run on E85
Generally, when you run more nitro, you run a colder plug. If your methanol percentage is low in a glow fuel, then your nitro percentage would be high and you would run a cold plug.
In my Gas/Glow experiments, the engines ran better with a hot, four stroke plug. I believe this was due to the low methanol percentage in the Gas/Glow mix, and thus a better or more reliable ignition with a hotter plug.
AV8TOR