I hate seals but manage to get them in one way or another, after ruining one. I swear the Elring seals are oversized. The last front seals I did, was with the plate removed. It was sooo much easier. Yes, those plate screws always seem to be loose while the plate oozes oil.

For the gasket, I may have used RTV but I know I did at the oil pan gasket. I used Locktite 242 on the plate mounting screws. Any service removable thread locker is ok and I tend to use this on many other screws besides the front suspension hardware. Note that a rear seal plate screw did work is way out and blew out of the trany inspection plate while I was going 70MPH.
With the plate off the car, I tapped in the seal with a flat piece of wood and a mallet. For the rear seal, I started it dry, no lubricant just enough so it sticks and is parallel. Then lube and completed the installation. Your fine if the seal is flush with the cover. If you want to recesses the seal a little, finish with a piece of plastic pipe.

Just for the halibut, here is the rear seal plate. I hope you never see yours.