Well, I got the inner primary off... what a filthy mess back there! Reminder, we're talking about a 91Evo/5Speed. The locking screw was lying in the bottom of the transmission sprocket, the lock nut was loose and it looks like it was slinging fluid on both sides of the sprocket. Easy to see how it would look like that with the sprocket loose.
There are small grooves worn in the spacer behind the sprocket where the transmission main seal runs. New seal needed there, maybe spacer too and maybe the seal between the inside of the main drive gear and mainshaft. Seals for the inner primary too.
I'm still at a loss to understand how transmission fluid is getting into the primary. I also don't know which direction I'm going to go with this - try to service the transmission myself or take it to someone. I don't have the tools to work on it or any experience either so I am a little reluctant to try to tackle it myself. By the time could buy the tools I would probably have paid for parts and labor. On the other hand, I don't know anyone competent to take it to.
I'm open to suggestions - what do you think, what would you do if it was yours?