I left the felt on and used the heavy-duty 3M. I'd recommend contact cement. I'm not that confident it'll hold. Of course, it is thick and the the backside is felted too (one side felted, one threads on the material), so that may be the problem. I'll be curious how it will work. Oh, and it took 2 full cans . . .
As for effort . . .
Wasn't that bad. EVERYTHING (except the c-pillar cubbies and overhead console) just clips out. he advise would be to watch and be careful not to break the clips (would make it difficult to put everything back on). First, pop off the handles and visors (all use clips-> be CAREFUL), the visor retention hooks (twist core and slides out, then base comes right out), and the overhead lights (front spots EASILY pops right out, but main has 4 clips that could be broken-> should have taken picts of that one). Then, pop out the 5 plug-pins (correct term?), pop off the C-pillars and A pillars, slip it over the B-pillars and out from behind the weather stripping (easy). REMEMBER: there are 2 wirelooms taped to the top of the headliner. I just pulled them off and taped them to the vehicle metal bows. The headliner comes out the back. Oh, and I'd NOW advise popping out the lower parts, to allow more clearance. I made it out by just pulling the top parts down and pulling over them. The edges of the headliner had to be forced out the door, but as I was recovering it I wasn't worried about it.
The front sway was more difficult, as was the strut bar. It was easy, just time consuming. Also, the specific fabric I used was more flexible than I realized, plus patterned, so was HARD to keep perfectly straight and square. It looks good in person. The photo shows the slight wave and off-square, which isn't noticeable in person (and until I saw the pict I took I didn't realize it was as crooked as it is . . . too late to worry about now).