Walking through a car show my wife always hears me mutter SBC as I turn away from most of the cars there. When she asked what that meant, I replied "Same Boring Crap".
If the breaker in your main box was "way too small", what size wire is hooked up to it? I hope it's #6! If you're pulling 40 amps on a #10, the wire will become a fuse!!! The breaker MUST be the weak link in the circuit!
Sounds like a recipe for a house fire! Find out what size wire you have and DO NOT exceed the amp rating for the wire size! You can easily unplug the low voltage "control" wire from a sequencer to lower the total amp draw of the heater. What is the KW rating on the heat kit in the heater?