David,
Very interesting cartridge you are working on.
QuickLoad is a PC software package available from
http://www.neconos.com/details3.htm.
I went without it for many years but finally bought it last year. It is really great for helping develop loads for unusual cartridges. It takes some time to learn to use and a good understanding of chamber pressures and what affects them. I enjoy using it and have found several loads that I thought I knew everything about abut have been improved by using Quickloads.
Lowell