That question has been asked before on this forum. I do believe that a search here on that topic will reveal at least one interesting way to solve your problem. I have saved that info for my future use on my 57 3100.
As I recall, it uses 80's k-10 centers for ralley wheels popular then and still today, which are modified for the clips required for your caps.
Search for it as it is worth looking at.
delky dave in WYO


1957, 3100, v8
2016 gmc 4wd