The 8 3/4 6-lug wheels were also found on many Ford, Dodge, International, and GMC 2 ton trucks and school buses into the late 1960's (and perhaps later). Most of these have 8.25x20 tires. Look for the lock ring on the dished out portion of the rim, those are the ones you want. They are out there, you just have to beat the bushes to find them. In fact I found another one just this week. It should be easier for you in NM.
Another donor would be the older military 2 1/2 ton trucks. These wheel and tire assemblies can be found for relatively inexpensive as the military has surplused all of their stock. These wheels are somewhat wider than original on a 59 Viking as they fit 9.00x20 tires. I think they should still work though.
If you are going to get into this old obsolete vehicle hobby, you must learn three things: patience, patience, patience. And above all else, have fun!
Good luck with your endeavor.
Paul
