thank you, that makes sense and gives me a direction to work with, much appreciated, although there are no bolts on the back of either wheel at all just the spline and a bolt which goes over the spline, so attachment will be a weld anyways? i'm not sure. the ring of metal for the 360 degree horn would seem to block any bolts of use and as there are no holes to even put a bolt of any kind i will need to look at a new boss to see what type of interface will suit. is it ridiculous to think a reducer or shim would be adequate enough to allow a safe interface?