I've got a 2010 quad with a stripped fcs fin hole, (read earlier post).
Haven't tried the permatex or jb weld products as I don't think they will last long. Such fine thread on the grub screws with metal to plastic is not such a good idea, especially if they are removed often.
The slot box is a much better idea.
I ended up using a slightly larger diameter grub screw with a wider thread. I drilled out the fcs fin box slightly and then tapped the hole.Seems to be working and the fin hasn't come loose as often.