I had a feeling I wouldn't be able to get the specs.
If I knew more about machining and had more time in the semester I would consider the shells. The class I am currently taking is basically an introduction to machining.
I did manage to get specs for the velocity screw off an old A-5 RVA at my home field. I may just use that and figure out how much material I want sticking out the back of the 98.