The great thing about Eternabond is that removal of the old caulk isn't required. It goes over and around the old caulk. Be sure and use laquer thinner as a cleaner, and knead the tape into the surface of the fiberglass with your fingertips. I have a roller, but still knead it in by hand. I did both sides above the bottom of the gutters so the roof won't blow off, both front and rear caps, and EVERY caulked place in the roof for skylights, pipes, TV antenna, etc. I've done 2 RVs now. I used acetone as a cleaner once and had some lift offs.
The bad thing about silicone is that nothing will stick to it. For caulk, I use 3m 4000 UV. If it never has to come off for any reason, I use 3m5200.
2002 Winnebago Sightseer 27c
Workhorse, widebody, narrow front track