These aren't liquid cooled engines. On glow powered boats that I run, temp is somewhat important. If there's too much water getting through, the motor won't produce the power. Obviously if there isn't enough, it will overheat. The ID of the nipple can be changed, or partially restricted.

On an airplane, air cooled, with constant prop wash cooling it....temp doesn't matter. It won't sound right if it's too rich, and it won't stay running very long if it's too lean. The same goes for the glow cars and buggies I run. There should be a noticeable smoke trail running at WOT. Transitions should be smooth, with a good belch of smoke.

When you shut down...if you spit or gleak on the head, it shouldn't sizzle. If it sizzles..it's too hot. The exhaust smell is another clue....I can tell when my truck is running too lean by the smell of the exhaust.

This is all that is important in regards to glow engine temps.

EDIT: A pusher setup is completely different. It then becomes like a car engine...and would require to be run sloppy rich, or have a large heat sink