I measured the dimensions of the tank opening today. The the door is 3/8 of an inch taller than the tank. How ever the platform the tank sets 0n is above the bottom of the door frame actual difference is less than an 1/8 of an inch. The width of the door frame is the same size as the tank minus the thickness of the weld.
I can get the tank in as long as I tilt it towards me about 12". The tank has to be perfectly straight to fit through the frame. However the welds hang up and you have to push the welds past the door frame.
The easiest solution would be to file a slot to accommodate the welds in the door frame. I would need to get some matching paint after the slot s filed though.
The up side is no one will be stealing the tank by opening the door grabbing the tank and running.