Because the blade on the CUDA isn't real wide, and to minimize obstruction, I'd go with the spin-mounted disk. In looking at the RT design, the disk is the obvious choice. A stud would necessitate a deep grove in the handle to facilitate opening, and thus ruin the sleek appearance of your knife design.
One more thing, what about toughening up the liner lock? I read that enough (human) pressure will cause it to bend.
Make it MA...and I'll make it mine. Honest.
EK
[This message has been edited by ekaagan (edited 18 May 1999).]