While the inner tub was out I drilled a hole through the ridge inside the outer tub to see how much room could be gained by pushing that ridge in. We gained 3/4" along that ridge point with a few hammer hits. There's plenty of room between the quarter and the tub along that line, but not much if you go lower than that line.
Did you do anything else toward expanding that outer tub? FWIW I took a left side outer and a right side inner and compared them and it sure looks like the inner could be used to get rid of that hump if a person was so inclined. Not sure if it could be done working from the inside with the quarter on though.
