Mike, I have a couple of suggestions for you regarding starting out with making hollow forms:

First, start with something smaller than 12 inches in depth. The deeper you have to hollow out the harder it is to do. Your tool is hanging way out over the tool rest. Much better to start with a 4" piece and work up from that.

Second, the tool you use is to a great extent a matter of personal choice. I have a guarded ring design by Hamlet based on a Jimmy Clewes design which I like, but I don't know if they are still available in the USA. A lot of people use a Hunter tool with a solid carbide circular cutting tip with works very well, and Easy Tools just came out with their own tool. Michael Hosaluk with be demonstrating doing a small hollow form using one of his hook tools on Saturday. One of the important features of most tools is that the cutting tip is in line with the tool shaft which minimizes the torque problem.

I don't have that much experience doing hollow forms, but some of our members do. Perhaps one of them will offer to mentor you on this subject. Good luck with it...