[aerohead]

The steel wheels flex and deform as they roll,'taking' the MOONs with them.Cast or forged wheels wouldn't do that,but you might not want to drill into an alloy wheel,as it could initiate a stress fracture.
I gave up on the bang-on style MOONs.The screw-on type deform as well and will eventually hog out the attachment holes.
The only 'decent' attachment involves the MOON,3-dzus,weldment system,which provides a welding template and weldments which are electrically welded to the wheel.
It's way beyond what most folks would be willing to deal with.
I've gone to a 1970s GM stainless steel bang-on wheelcover which Oldsmobile and Buick used.They're slightly convex,have brake cooling vents,mount rock-solid to the wheel,and run silently.