some things i've picked up from threads on other forums..
methanol burns cooler than gas.. so changing to gas can cause overheating issues, especially in enclosed cowlings. you'll notice gas engines have large head fins.
glow can be converted by using the electronic ignition systems found on aftermarket gas engines. or adapt a flywheel/magneto system. you can buy off the shelf spark plug to screw into the glow plug hole.
consider that the ignition system will also add weight to your model.
warbird fan and old toyota's