Follow up:

So I went at the sunroof in the wagon tonight.
This is on an 87 745, using a 91-ish sunroof, the non-crappy one.

I pulled the roof panel and the track assembly out the top.
Really did not want to muck up my previously recovered headliner.
Came apart alright. Went in alright. Pretty much.
There is one screw on each side that has no place on the 87 pan, but I don't think it'll matter too much.

Now, trouble is, it will not retract. I have vent fine. Both sides are in sync I'm pretty sure after several double checks.
There is a gap at the front edge, might just be a seal, but there wasn't a gap before. And even at the up most adjustment up front, it's still not quite high as it ought to be (1mm below the roof), and there is a lot of play up and down in front as well. Just worn out?

On the rear slide problem, it's the rubber/plastic dealy that pushes down the little catch on each side to allow it to retract. Even with the roof panel off, I have to manually depress that little catch a bit more to let it retract.
Tried all adjustment positions on rear of sunroof, and the front is up high as it will go and still a little low, so. I'm stumped. It really don't look particularly worn out, but could it be? Can I bend those tabs that depress the rear slide lock a bit to get them to engage? Is there an adjustment other than the roof panel height I'm not seeing?

And it was way to cold at 11pm to be screwing around with this thing..

Thanks..