1987 Chrysler LeBaron Oil Pan Gasket

Oil pan was damaged slightly (small hole near drain plug) on a median. Got
the pan welded and sealed up again, but now I'm having difficulties getting
it back together. This is the 2.2 liter turbo engine. There are two rubber
seals that are supposed to seal the front and rear bearing extension area
(big cutouts in the oil pan). The front seal (right) fits fine, but the
rear seal (left) on the bell housing side is giving me fits. This is also a
critical fit area and is more or less blind due to structural interference
and an aluminum bell housing cover plate. To refit the oil pan you have to
insert the flange into the small space between rubber oil seal and this bell
housing cover and then push it slightly. On my previous attempt, the rubber
oil seal was displaced out of its seat and oil was leaking big time into the
bell housing. Took it all apart again, cleaned off all the RTV, got a new
gasket set, and found out that the rear (left) seal seat casting is just
slightly too small for the seal. I sanded off some rubber on both ends of
the seal to make it fit better, and applied some high tack sealant to
hopefully hold everything in place when I go to bolt it back together.
Anybody else ever have this kind of difficulty or can recommend a different
way to proceed? MB