A genuine "Snap-Off" adapter takes a standard "6-hole pattern" wheel & boss. Most aftermarket wheels are "6-hole pattern" so this isn't a problem, just be aware that the Mountney "Classic" range while having 6-holes is not the same pattern and will not fit. I bought mine several years ago and having been asked this question before I have already checked and found that the company has either stopped trading or changed name.
This link Snap Off: The Best Security Money Can Buy will take you to a website which shows the kit I have fitted, just use the link page to contact them.

Thanks Litch, seems tempting.