Sorry if I get this wrong , haven't the chance to read all this stuff yet...

on "running out of room" I was referring to room on the bracket on the axle needed to oval the holes out enough. The hole in front of the axle would bottom out the trailing arm inside the braket before you could move it much.
The rear hole gets ovaled downward. Not much metal left on the braket not cutout. I was going to weld a washer from a trailing arm onto the braket. The hole is exact size for the bolt.
I have not done this project yet. just alot of measuring.
I just put my 13mm lenghtened driveshaft in this month. If this doesn't stop the vibes ,,,then I'll do the pinion angle change.
The guy that made my driveshaft said there wasn,t enough change to make a difference. I think it does matter.