FWIW...I'd check with the State Transport Regs... such spacers may be illegal... Spacers can increase the (shear?) loading on the wheel studs because of the spacer gap between the flange and body of the wheel. I (reluctantly) used spacers (10mm) on a camper trailer to accommodate electric brakes... which is where I came across the Dept. Motor Transport references to their use on cars.
Also, I seem to remember some engineering advice back in the long dim past where it was good practice to have several "excess" threads clear of the fastener once it had been tightened to spec. I'm sure there are others better versed in these matters who maybe able to clarify...