Porsche Cup3 Rear wheel stud length

[yetibone]

Has anybody here used C.B. Performance's Roto-Hub disk brake conversion to mount 17" Porsche Cup wheels to a 1302S? If so, where does one find studs long enough to achieve
the proper backspacing in order to keep the inner tire/wheel from
rubbing the farthest front, rear control-arm bolt, and rear suspension bump-stop. The studs that came with the disk brake conversion are about half the length nessasary to space the wheels out properly, and C.B. Performance was not helpful in supplying, or finding what I need.
I have serched locally (Raleigh NC) and came up with nothing.
in fact, most places I inquired within, got a good laugh from what I asked. Please reply if you can help, or know of anyone who can.

PS, The hubs are threaded M14x1.5

Yetibone