There is actually a much easier/better way to install a fighting butt on a rod. The problem with the threaded inserted butt is that the insert only fits a very select few reel seats made by Pac Bay which most likely neither of your SC or BPS rods use. So the best way to do it is as follows....
2- Remove the end cap from your current reel seat (some light heat will loosen the epoxy and then pry it off.
3- Take a short section from a broken rod and trim it so that it fits up inside your rods blank (insert about 3" of it into your blank where you removed the cap from). Make sure it fits snug and then take it out, cover it with epoxy, and reinsert...let dry.
4- Trim the section of blank you just epoxied in so that it is the same size as the fighting butt you bought.
5- Ream the ID of the butt to fit the section that is now sticking out of the rear of your rod, then epoxy it onto it.
6- Fish and repeat
That is a great idea.... I think I will experiment on a couple of older rods first though.