Hi looking for a supermoto rear rim 5.00 just need the rim no hub needed

afternoon all, just got a top deal from gear4 in peterborough for a supermoto conversion kit for my 250 exc that's been boosted to 350 with the ktm kit. only thing to be confirmed is wheel size - they've recommended a 3.5" on the front and a 4.25" on the back, but most of the advice i've had up...