917 wheel spacers... Wheels studs

I have recieved from RCR 4 wheel spacers 4x35mm.

For the front, I need to be reduced them to 18mm. (I've got 10" wide front wheel). It will be done soon.

For the rear wheels, 35mm is almost perfect, but I will not be able to install correctly the big nut in the center (only few milimeter). I would not be able to tork it safely.
I need to change the design.
I will add a spacer on the hub.
For this I need to change the wheel studs.

Does any one have a reference of the one used on RCR kit ? (I heard it was from C5 Corvette)
Where can I found longer wheel studs (1 inch more)
I had some concerns about the centerlock nut engagement - when torqued the face of the nut is more-or-less flush with the end of spindle, not like other designs I've seen where the spindle sticks out and is locked w/ a cotter pin - but it's been fine for 4 years and I havn't found any thread damage on the nut/spindle from torquing to 310 ft-lbs (and the nuts have never loosened even though I anti-seize the hell out of them).