I'm assuming by rugby team, you mean rookie team?
If you're not sure if the wheels you're looking for are legal or not, I'd encourage you to spend some more time reading the manual!
Most wheels are legal as long as they don't damage the field or field elements.
Your best bet for finding wheels in the size you want is to do a bit of research, and if you find something but want to know if anyone else on CD has tried that product, then post with that asking for opinions.
Obvious places for wheels that others are using: AndyMark, Harbor Freight
I've been out of the build season game for a while though!