A 5' blade is the right width for a BX tractor. A smaller blade set at an angle will be narrower than the tractor. A larger blade will be too much for grading with a BX. The weight of the blade is also important. A light weight blade (150#) will work for snow removal, but will bounce across the ground if used for grading. A 250# rear blade works good on my BX2370, and the manual says you can go to 350# for a rear blade. However a 350# rear blade may be difficult to control with the simple hydraulic system on the BX tractors.