In need of some new boots before winter for ploughing with naud that has 14"share and board working width. New to me tractor on 600/65r38 and 480/65r28. The rears are michelins and seem to measure close to 530 actual width. Currently plough with different tractor on 420/85r34 and get along fine especially when slippery, wont be using this tractor anymore before suggested. Can i change rears of new tractor to 520/70 r38 and keep existing 480/65r28 fronts? I think a true 600/65r38 will leave a lot of trampling and be more slippy. Thanks