I am in the same boat......body guy cut out my headliner with a razor knife in 2" strips so he could get to the moonroof seal........before he figured out if you open the roof the seal is there. My roof was dealer installed and is branded Holandia. I found out that they were bought by Webasto and there is a dealer 15 miles from me. He gave me a sample piece of seal and it fit perfect. Got the new seal for $40.00. I took my car to them to see about getting the headliner done, I showed him the options available for ABS headliners. He said to get the hardtop style, uncovered and bring it in to him and for $250.00 they would cut it, install the foam on the board and the slider, let me pick from 17 shades of grey fabric they have in stock on enormous rolls.
I talked to them for awhile and told him I needed to dissassemble my roof to get all of the primer, dust and crap out of the tracks. He showed me the screws to take out for the glass and the track, the slider came out after the track was removed. I spent most of a Saturday cleaning the junk out of the tracks and reassembling and testing before I installed the new seal. Roof moves much faster now and actually seals now. HTH
Bryan