I think I found the source of the leaking.
The problem is that the OD of the CV changes to slide into the inner bushing/bearing. When it necks down, it's filleted. This rounded shoulder is where the sealing surface of the new seal is trying to seal. Basically, the larger OD of the axle isn't deep enough into the seal to stop leaks.
So, I can't ram the new CV in any further. The shoulder is more or less flush against the bushing (I removed the seal and put in the CV to confirm).
I spent about 1/2 hour measuing the remnants of the OEM Delco seal and the three new 3543 seals. The OEM seal has its sealing surface very slightly further out from the diff cover than the new 3543 seal (about 0.060" according to my calipers).
This additional inset of the sealing surface along with the radiused shoulder is causing the leaking.
Two questions:
1) Is the output support support (passenger side differential) a bushing or bearing? It looks like a bearing to me but I cannnot for the life of me get the inner 'race' to turn on what I presume to be its rollers. I haven't wedged anything in there to try and turn it as I don't want to break it or anything.
2) Are the shoulders on these CV joints typically filleted like that? If it stepped up rather than gradually radiused up in OD, this seal would work fine.
I WISH I still had the OEM CV to measure. I have a feeling that the larger shaft portion on it extended further into the diff housing making the seal more effective.
Right now, the new seal is basically trying to seal around the shoulder fillet that has a much smaller and non consisent (along the axle axis) OD. No wonder it leaks....
If I don't fix this soon I'm either going to go crazy or my wife is going to kill me for spending so much money and time on my "stupid car".
