Yup, I had thought about all of that, which is why I got some spacer plates to see if I can mount these on the truck to check clearances everywhere, even off-camber it a bit around home although it’s not really intended for being used off-road. Figure out just what my clearance is everywhere so I can pick the correct spacer. These plates are 5/16” thick and definitely not a long term solution or something I’m going to want to drive super hard with, but they will get me past the center bore on the axles so I can test fit the wheels. I have a different rear axle than Josh, so I’m not sure I can just go by his spacer size and expect it to be correct. But his input is still valuable because it means I’m likely to need at least 1” spacers all around which also means that I probably will not have to worry about milling out the center bore of these rims, just get spacers that have the bore size I need.
I would never drive on it, but if you want to test clearance, you could just start with a big box of half-inch washers And shim out the wheels using three of the lugs, or even drill out some plywood or such.
In the old days, 80s/90s, several times I put Dooley wheels on the back of a three-quarter ton Chevy. I think we did it on a I think we did it on an F250 as well. They had to be spaced out. We started by putting Lugnuts on the studs (without a wheel) but reversed. If you think about it a second, when you put the Dooleys on you reverse the taper facing inwards. I think we ended up with a couple of Thick flat washers, that we bolted to the wheel with reverse lug nuts, mounted the wheel, and then had Lugnuts on the outside. If I recall, right, we actually had to get longer lug bolts and turn down part of them and thread them further. That was a challenge because it was all hard steel.
I thought and a disclaimer. That meant we bolted the drum to the drum assembly before we put the wheel on, and then we bolted the wheels to that. Some people would scream that that was unsafe, but I don’t know why it would be, and therefore I don’t advise anybody do that.
We modified those trucks because we pulled a lot of trailers, and the Dooleys always seem to track better with the trailer. We added a couple leaf springs, so clearance under the fender wasn’t an issue, but they would sling mud, So we yeah, today 2 inch rubber bumper fender trim thing to contain the mud.
My point to you is that you can use three lug bolts and use anything on earth for a spacer as long as you do it evenly, to check geometry in the driveway. Then you could get the right size spacer. You might need to get it too thick and turn it down if it’s an oddball number, or maybe use full Diameter perforated shim plates behind the spacer. One thing most people miss on thread locker, is that it lock surfaces together. If you ever use multiple layers like that, put the red thread locker on the surfaces of the things you put together just before you torque them down.
My two cents, albeit this is two WWII steel pennies from my demented mind that built the Road Ranger, only offered to help think it out.
Might be interesting if you took a couple of pictures of the hubs along the way (Since you’ve got nothing to do)