Some good and valid comments here; I especially have to agree with TommyBoy's comments. I have installed connexion hinges on 2 different Hill bows and they both turned out just fine. However, I did them both from blanks rather than an already-finished bow, so it was a retro-fit in the sense that is was already tillered (by Craig) and finished (by me. I had Craig leave the back of the handle square so that I would have plenty of width to fit the hinge. The problem with one that is already finished is that the back of the bow in the handle area has probably been rounded enough in the finish shaping that there is insufficient width for the width of the hinge to seat on properly.
It is a relatively simple project that doesn't change the tiller of the bow - at least from anything I could measure, and the shooting characteristics of my latest Redman 2 piece are great. The hinge does add a little bit of extra depth to the handle, but you can take a little bit off the belly side to compensate. I don't find the additional bump to be a problem at all.
After looking at Big Jim's "how to" on the fiberglass sleeve I have seriously considered trying that on my next one, although I am fine with a straight grip, so the metal sleeve works for me, too. However,if I went the fiberglass sleeve route, rather than cut into the glass backing I believe you would want to leave the glass intact and use overlays to get enough depth for the fiberglass sleeve. That would still tend to increase the overall depth of your handle in the same way that the connexion does, though.
If you really think you would like a take-down, though, you might consider getting the blank and doing the connexion hinge on it. That way you can shape the finished handle to suit yourself.
I have a HH Tembo one-piece that I finished from a blank and I have the Redman TD. I like the TD feature, but, frankly, I have yet to use it in a way that I can't use the one-piece.
If you decide to try the fiberglass I would certainly like to see your results posted. Good luck.