I am working on my first segmented piece - more of a partially closed form than a hollow form. In the past I have thought of the advantages that building a segmented piece (bowl or hollow form) up ring by ring would present over beginning with a blank as I have in the past. The benefits and ease of shaping and sanding the interior every few rings sounded nice. However, now that I am there (I have my first 5 of 7 rings glued together and on the lathe) I am kind of stumped and I have to assume that I am not the first one to try to figure this out. Here's my dilemma.....

In order to sand the interior of my first five rings, obviously I have to have the finished interior shape. But I don't have the final exterior form yet and I don't see how I can get it until all the rings are in place, and can view the piece as a whole. I don't want the inside to limit what I can do on the outside and I want to achieve a uniform wall thickness. I am concerned that attempting to totally finish the inside might make those goals difficult to achieve. At the same time, I'd like to be able to take advantage of the ease that not having all the rings in place offers. So I am rather stumped. How do others handle this?