Although I have dedicated frames for all my barrels, I've taken the barrels off many times without having to rezero them, but I use a torque sensing screwdriver to install the screw, the same setting for all of em, so they're always the same.
The TC forend leaves a bit to be desired too, I have an Encore frame with a .375H&H Prohunter barrel and t-hole Flex-tech stock. Before I ever shot it, I did a lot of research on it. The forend may need every bit as much attention as an H&R, fortunately, it's also easy to do. I made pillars to float the barrel for mine similar to Davemuzz's, and made sure the "ears" that cover the frame pin don't touch the frame, it worked well.
One option that a lot of Handi owners that have multiple rifle barrels on a frame, is to buy an extra forend with the barrel that can be "tweaked" to optimum accuracy for that barrel and is dedicated. One issue that isn't applicable to the TC is the forend stud isn't in the same identical positiion on every barrel, the forend has to be adjusted to that barrel, once fitted, bedded or whatever, it should be completely repeatable when swapping barrels.
As burntmuch mentioned, indexing the screw is one way of making sure it's the same each time, but won't account for changes in compression of the wood or weather(humidity) and temp changes which can make a big difference in the fit of a forend.
Tim