Welcome aboard, glad you found us and posted. The M1 engine was designed from the ground up to be a multifuel engine. Most aircraft in order to keep a low weight to power ratio use engines optimized for a single fuel type. I think the power loss that would come from using an unusual fuel would cripple most aircraft. Not to mention different corrosion and temperature characteristics would wreak havoc on such finely tuned systems.
I was always a little irked that GDW did not differentiate between kerosene and aviation gas but it pales in comparison to my utter disappointment in finding out that their methanol production ideas were pure fantasy.
My Methanol Thread