[Dan in Pasadena]

AFJuvat, You can't physically put a wrench on that 21mm nut - no room.

I think Pokey gets the prize on this one. I shoulda thought of it. Should have gone down to Harbor Freight and bought a couple cheap ass 13mm wrtenches and groun one down to the thickness of the old, old style "tappet" wrenches for old American cars.

I ended up putting it together as is. Re-indexing the lifting arms corrected the problem, but the torque is still too high. I will just tell the new owner not to open/close the sunroof more than necessary and to do it while looking at it, not with the radio blaring and the cellphone at her ear (yeah, right!). Oh well, it works and it wil be her problem after Saturday.