What wattage CHE to get for best performance with rheostat?

Hello,

When using a RHEOSTAT, at what setting does a CHE perform best?

Lets say for example I need to use about 75 watts of power.

Would I get better results running approximately 75 watts through a 100 watt CHE or a 150 watt CHE?

Do CHE's typically function better and last longer when using less of their normal operating wattage, or when using close to their advertised wattage?


Thank You.