Hi. I'm the person with the Alaskan on a flatbed that you saw in Grand Canyon. I'm also full time, and pull a two mule aluminum 4Star trailer, usually with one 800 lb mule in it. If you see this post soon you will probably find my truck in the same place until Sunday afternoon. I'd be happy to talk about the spare tire carrier. It came from XP Campers and has some drawbacks, but if you are a metal worker you could probably base a better design on it. I put it on the truck so I would have 2 spares. A friend put it on his truck so he could put an extra diesel tank under the bed where the original spare is. Both are good modifications.
The main problem with my carrier is that it has only one point of attachment, which is insufficient for an 80 lb. plus wheel. It can flex enough to impact the cab.