Lots of mfr's use only RTV to seal the oil pan to the block. ZuZu 2.6 is like that, with its cast aluminum main pan which uses no gasket. If you were to put a gasket in where there's not supposed to be one, it could mess up critical clearances. I recall doing a Cast-Iron-Duke 2.5 in an '86 Jimmy and there was no gasket, just rubber seals fore and aft plus RTV on the rest of the block. That being said, using a gasket on the oil pump flange, if it doesn't change how it fits in the space it's in, ain't gonna hurt anything.
Be sure you're extremely sparing when spreading RTV sealer on critical areas such as the oil pump sealing surface. Very thin bead and you can use a rubber/vinyl/etc gloved finger to spread-out the sealant. You don't want a big gob of silicone oozing out into an oil passage and hardening/blocking.
I've used the Permatex Gold sealer for pans before, it works well. But the Permatex Ultra Grey is a newer product and likely better than the Gold:
Far as priming the engine goes, does the manual have any suggestions on that? I'd think that you could spin the oil pump pulley before you install the timing belt, and that would do a pretty good job of priming the engine. Chuck a socket adapter in a drill motor and prime away!