I would have to double check but I did cut a plenty big hole in it for each of the studs and spacers. But maybe one side is causing a problem. But even the collar is an issue because the heater kind of goes inside the collar on the back side. So even if I were to be able to get it to go back another quarter inch it will hit the inside of the collar.

I was thinking about taking the collar out altogether and mocking up just the heater and taking a few measurements to see where it sits in relation to where it is now.

Thank You, I am very quite happy with how the powder coating turned too.