Well, I think the darn thing just flys to slowly to provide adequate airflow.. its like it is always taxiing.

Alluminum motor mounts would help draw some heat from the case. And then you could have sheet brass or alluminum bolted in between the engine and mount to increase the area even more.

There are fuels with more oil, that might help some. The answer will most likely come form the shotgun approach. try everything !!

Run it as rich as you can, for sure.