Rxter,
The first time I replaced my sunroof gears I cut through the headliner to get to the mechanism. I made the cut under the trim panel that you remove to get to the sunroof mechanism. This approach seemed easier than trying to remove the headliner from the trim edges, and did not show any issues once the trim panel was replaced.
Anyway, that's where I got a few strips of vinyl.
I know you have a cab, so this won't work for you.
The piece I sent wasn't very big at all. I'm guessing about 1/2 by 1/4 inch, but I'd suggest calling them to see what they need. They may even be able to work with something smaller that you can snip from the back side of the door panel where it wraps around.
There may be a good spot on the cabs that I'm not aware of.
Jamie