Sunroof fun today. The rear getting stuck open in vent mode gave me a little inspiration to remove the rear glass (4 t25s and some wiggling). Cleaned the tracks and replaced both seals: one that goes all of the way around and the one which goes across front lip of rear glass.
Once the rear glass was out the deal change was rather simple. Temps in the 60s today helped.
Old seals were a lot flatter than the new ones.
Still could not figure out how to fix the little "wedges" that cause rear glass to vent up. At this point the motor pulls them forward into vent mode (lifting the rear of the glass) and I can manually move them backward (lowering the glass). The pieces seem solid, the cables move in the track together, however the motor will not pull them backward (lowering the glass). Seems that maybe the common part to break here is not in the tracks but up by the roof motor ?
Anyways leaving the rear screws out of the rear glass indeed allows all parts of the sunroof to function just fine without the rear glass venting.
I will say very marked improvement in the rattle factor. Overall sunroof is much quieter with road bumps now. Seal replace is rather easy once you sort rear glass removal.