RE: Nexstar problem - Loose horizontal stab
The screws should be pulling the fin down tight on the top of the horizontal stab and pressing it tight against the lower surface of the groove cut into the fuse. I'm not too worried about the gap between the vert fin and the fuse if the other part is good. I'm just wondering it the bottom of the vert stab is hitting on something and not settling into place properly.
I don't know about the sticky tape. I would have used a layer or 2 of heatshrink tubing. But I have a lot of that available and many people don't. Tape SHOULD do it as long as all stays tight.