Installed the left elevator tip fairing tonight (pics show it flipped over).
This is the first fiberglass fairing that I've actually permanently attached. The other fairings I've made have reinforcement strips bonded with epoxy flox to the inside edge--this prevents the rivets from pulling through when installed. On this (and the other empennage fairings) I used ProSeal to bond the strips to the inside of the fairing. It holds much better, but if I had to repair the fairing, I'd probably have to replace it.
In the second photo, the front edge of the counterweight is covered in epoxy flox. I debated using fiberglass, but think that this will work well. I'll have a good bit of sanding to d to get the CW smooth.