[MTCK]

What you describe is exactly what I'm having made. Pretty low tech but it makes a huge difference. Pic is of the cold front I had made for my '77 daily driver. I think it was $80 about six years ago and now they are $125.

Circulating heater works great. Heater doesn't blow hot right out of the gate but it doesn't take long. 1500 watts is a lot but so is 7 or 9 gallons of coolant (I can't recall the capacity off the top of my head). Fires up like its +50 out.

If I can just get this defrost working and maybe an auto start it'll be a viable winter driver. I need it to be because it is my kid hauler on days when I'm moving the bambino around.