Tom I certainly am no expert on this subject but I am willing to share my dismal experience with the rear main seal.
Mine was leaking, a number of drops overnight, when I purchased the jeep nearly three years ago. It was needing an engine overhaul but the fun-money account wasn't there yet. I wasted good money on seal renew concoctions. So I, like you have done, started studying up on the subject.
I decided to do the in-place replacement. So I jacked up the front end, dropped the oil pan, removed the lower bearing housing, and loosened the middle main bearing a bit. The engine had the old style seal, the seal had a shoulder the laid over the housing edge. I used a piece of heavy copper wire to push the upper half of the seal out of its groove. Cleaned things up. The replacement seal was the Best gasket. Installed it, using a small amount of sealant where recommended. Put it all back together, started it up, and it poured.
To not bore you with all the details, the Best gasket was deemed defective and was replaced with the same results. With the upper half of the Best gasket in place , the lip on one side was tight on the crank surface but the other side was loose on the crank. I hoped when the lower bearing half was installed compression would correct this situation. But no luck.
I shoved an oil absorber mat between the oil pan and bell housing and lived with the 'tampon' for a while. I did try a Crown seal but it was a poor fit, too loose in the grove. I tried a Omnix seal but could not get the upper half to slid thru the groove. So I went back to the 'tampon' until this past January when I rebuilt the engine.
With the engine on the stand the first thing inspected was the seal. Nothing looked out of the ordinary, the crankshaft was polished. My buddy helping had used a seal he got from Summit Racing on his f-head and had good luck with it. So I tried that one, I think it's an Omnix, it has the shoulder that fits over the edge of housing like the original seal, and with 140 miles on it so far no drips.
I know some here have had problems with the Omnix brand seals but, for me, it's working for now. Best, no pun intended, of luck with your repair.
Bill