Sean, as Mark quite correctly points out, the two surfaces need to be almost touch dry before you join them together. We use an industrial spray glue and it is really the only best way of gluing carpet material. If you could remove the panel from the car, and bring it to my home, I'll get the job done for you.
Incidentally, talking about good trimmers. Short story. Guy across the road just bought a second hand C200 Compressor with soft top - 2007 model. A main Mercedes premium dealer refused a warranty claim (after two months of purchase) on a roof problem. The roof is operated by an enclosed cable that runs inside a heat pressed flap (by the factory) which acts as a glue. Well, the "glue" let go over a stretch of about fifteen centimeters at the side of the rear glass window. So when the roof was erected, there was an 'air gap' where the material had let go. The dealer said "sorry, you're on your own" (the car cost him $60K.), so the guy approached a "CLASSIC something" upholsterer who advised that the soft top would have to be removed at a cost of $1300.00 to correct the problem. We solved the problem for him by invisible stitching, at a cost of $50.00. However, only time will tell if this is going to work on a permanernt basis. My phone number ? 0428-50-1800. Regards Styria