Mate move to Clayton and find out how quickly you need a dew heater.
Where I am I use the dew heater terminal on a Mount Hub Pro at full belt on both my FSQ and my RC12. No distortions seen as yet.
Now for your RHA I am not sure, there might be some tube currents.
I use also a Dew Buster unit. It was cheaper than the Kendrick and has worked flawlessly for years. I don't know if those are still available.