Kendrick Dew Protector

I have a Kendrick dew protection strap that I want to use for a 10" newtonian. The tube is about 60" long. Where should I put the strap and how high can you crank the heat up on the controller before the image quality degrades?
Thanks

I think the dew straps are intended for refractors
and scopes with corrector plates. On a Newt you
probably want a small heater behind the secondary
mirror. And possibly one behind the primary if you
have really wet observing conditions.