I don't know if this is the case with your rims, but years ago (well, decades really) they used to make rims with oval holes for the lug nuts. You then had different inserts, one per lug, you could use depending on the bolt circle on the axle. I don't know how long they manufactured these and, for all I know, maybe they still do. Anyway, I thought I'd bring this up in case that's what you have.
Mike Mileski
Tucson, AZ