Ours isn't adjustable. The 2 rails are carriage bolted thru the campers wing floor. There are additional holes in the rails but spacing is greater than rails could move in the box, using existing holes in camper. Easiest would be redrilling thru campers wing using alternate rail holes- however I didn't.
I had lined our metal box/ door few years ago and the hooks/slide locks were pushing, cutting into insulation on door. To compensate I used file to elongate the square holes in rails ~3/16" toward door so rails could move back. One thing to check is clearance at back between tank and wall to ensure there's room to move tanks back.
The other is that it's the tank or slide locks that are actually hitting or pushing door. Dependent on door & frame design but again on ours the sealing flaps door offer quite a bit of resistance. However after adjusting rails the door would move in/out. I assume something bent using/latching before adjusting rails, I re-bent the door latch arms a tiny bit to pull door tight.
