What looks good on your tractor (Rear Tires) depends on what you like. I stayed with the standard size because my rims where in great shape. A little wider rim on the rear will push the rear end up a little and you gain some ground speed on your tractor rides. I like that look too as I think it makes the SC seem a little bigger like its big brother the DC. Some of the purists would say stay with the standard size.
Bottom line make yourself happy Zach!