I get the bronze bushings at my local Tru Value hardware store. If they are out of them, the local Ace hardware store usually has them. I don't recall what the exact diameter is, but I use a 5/8 inch drill bit on the wheel and the bushings that I buy will slide right in. Sometimes I have to use a soft hammer and a correct size socket to tap them in. Combine all of this with new axle bolts, and you will have wheels that will turn smoothly without excess wobble.
Thanks, I'll check into it. Nice pics too, that should work really well.