Hey David, I enjoyed your gallery story, I just got my 3100 back on the road last year and had the same concern about attaching the felt strips to the inside window trim. I realized that there was no way to replicate the staple technique the factory used so I improvised. That "fuzz" is somehow embedded into a strip of very dense and thick mastic. My answer was to clamp the felt strip to the inner trim piece (all off the truck) and I drilled 7 evenly spaced 1/8" holes thru the fuzz/mastic and into the inside trim piece. I then permanently pop riveted the two pieces together. The head of the pop rivet embeds into that mastic and gets nowhere near to touching the glass when rolled down or up. My one picture w the pointer shows that you can barely see the rivet head (that's the whole idea, right?) especially since the rivet is black.
Felt Strip/Pop Rivet
