Hi, just saw this. Mine is a plastic shell head that has good space for airflow. I have a fan in the muzzle right in front of my face. It gets hot but not unbearable, I would guess it reaches about 105° F. I can go up to about two hours without overheating.
The central hub for MLP fursuiters is on Facebook, search for the group named mlpfursuiters. Everyone there will have advice and examples.