I have had two different touch guitars. The first was a Chapman Grand Stick (12 string model), The second was an ADG 8 string (Made by Warr). I have neither at the moment, so I am sorry to say I cannot be of as much help as if I still did.
I think that before you pursue this further, you should consider how you will be playing the touch guitar. The tunings on these instruments are vastly different. On a Stick the lowest strings are in the middle of the neck. The 8 string Warrs and ADGs are more like extended range basses. low to high. The Stick had stereo jacks, the ADG a mono one. From a guitar players perspective, I liked the ADG set up better. The "inside out" Stick tuning was mind boggling after twenty years of guitar.
The Stick had rods for frets, round stainless drill rod-like pieces of metal that give an excellent feel. The ADG had large bass like frets. Both had a dampener (the soft half of velcro) and a zero fret if I recall. Look on the Warr and Stick websites. I am sure you will learn a lot there.
As for bridges, I think that individual saddles mounted to a piece of aluminum angle would be your best bet. Pickup wise, something like a Bartolini seems to be what the ADG had in it. It sounded good for bass and treble tones. The best pickup would be someting that doesn't require individual poles, but rather has some sort of bar design. (like a Hot Rail if that makes sense). Maybe you can contact Bartolini and see if they make pickups for touchstyle guitar.
You should be able to get strings and gauge recommendations from Stick and from Warr. Good luck,
Bob M.
