Don't worry, Gorilla Glue sticks outstandingly well on robarts. You can slightly roughen the surface for better glue adhesion if you still are skeptical.

I have a 33% Extra with the big robarts (3/16") and I use only 4 per elevator half and each one has only 1 or 2 barbs. When I glued them, I was worried too and checked them carefully only to find everything else will blow away before the robarts...

3D along with IMAC flying for almost 2 years now with this setup and it is as good as new.