OK little help here please

I'm looking to put some 12mm studs in my drums to bolt some MWS BRM's to .
Found the studs I want no problem but the wheels have 15mm holes for the bolts / studs .
Looking about for some sleeved nuts with a 30 degree washer all I can find are 41/64' bolts which work out at 16.27mm .
Anyone got any idea's as I don't want to run without sleeves and risk the wheels slapping about on the threads .
I'm sure I must be missing something here

I've seen guys running what look like a brass looking cadnam plated nut on a stud looks very pro

all I seem to able to find is either silver or nasty chrome
HELP
