Did you ever have one of those builds where the paint just won't cooperate?
After the problem with the silver fins:
I wanted to lightly sand a few small raised spray bumps on the tunnel.
I used some cheap Harbor Freight 500 grit sandpaper.
It discolored the tunnel a gray color!
The Tiny Tim booster was painted without problems.
The entire lower section is simply painted black.
The Kevlar will be tied to the clear plastic tube.
A small hole is drilled using the tip of your hobby knife.
The knot goes on the inside, so a slot is made to run the Kevlar forward on the outside of the tube.
I started a "V" notch with my knife, the deepened and rounded it with a diamond file. I made sure the notch was deep enough by setting the Kevlar in the slot.