Thanks everyone for the info in the thread. It really helped, as this is a big unknown area.
Some additional info:
Problem: Rear corner of sunroof stays down, will not sit flush.
Probably the cable or cable pull on one side broke- per this thread.
I wanted to get the sunroof to sit flush again, and not concerned with using it again (rarely use it).
Just wanted it to be weathertight again.
Solution:
1. Take off surround trim (fragile and probably will crack and break all the tabs)
2. You will see 6 cad plated 10mm bolts, three per side. Remove.
3. Lift out sunroof and store carefully (i just set it on the roof)
Now it is very easy to access the mechanism from the top.
4. Use a flat tool to push the mechanism towards the front of the car. It will rise, and you can feel it lock in place.
5. There are metal shims between the sunroof frame and slide. These lift the glass into flush position.
You can add washers to fine tune the glass to sit totally flush with the roof.
I added one washer per rear bolt, just to get it to sit flush.
My tilt works fine. So I can still vent if I want, though I will probably not touch it again!
I would not try to wedge a screwdriver or anything in the rails. It is just so easy to pop out the glass and have much easier access, clearly see the mechanism, and not potentially gouge or damage anything.
Total time: 15-20 min casual