For a long time, I preferred to have natural seams between the elevator/rudder skins and their fiberglass fairings. After looking at the elevators and rudder with a critical eye, I decided that there's just too much waviness and seam inconsistency for me. (The 4th photo below--a "before shot"--shows the issue. It's almost impossible to avoid seam inconsistencies because of the overlapping aluminum skins along the sides of the caps.) So today, I made a lot more work for myself by filling the seams:
1. Sanded the end caps and skins with a 60-grit hard block.
2. Cleaned and prepped the areas.
3. Applied a moderately thick mix of flox/micro to the seams and skin overlap areas at the tips. Used a credit card to taper it down into a somewhat feathered edge, for ease of sanding tomorrow.
I'm sure this will make the control surfaces look great, but I hope I won't think of this as a mistake years from now. I'm hoping they aren't susceptible to cracking. (I am going to leave the small seams on the HS and VS caps, because those look great.)