Another update:
The tires finally came, and today I cleaned up the rims and tightened the spokes, and then painted and clearcoated them.
After that I installed the Bell no-flat foam tubes and the Maxxis Slick Willy tires. Oh my f****** god are those things hard to install!!!! Took three screwdrivers to pry the tires and tubes onto the rim. But there is ZERO slack inside the tire, it is one solid tire/tube combo on the rim. I dare say these might actually be good for motorized bicycles if anyone wants to try them.
And a picture of the finished result:
I will be installing the wheels onto the trailer tomorrow, and then I need to put air in the new tube in the front wheel of my mtb. Had a blowout the other day and bought a Bell version of the Slime tube I have in my back tire. Will take another picture with the wheels on the trailer and the trailer attached to the bike.