Perhaps you could use a jack and / or boards to raise the low side of the loader or perhaps you could remove some dirt where one wheel of the tractor goes to get it level with respect to the loader.
Why not just make thinner cuts with the 60"? Depending if you are just cutting grass, I would put a sharp edge on the 60" cutter blades. That will not work if you are cutting anything woody. Good luck.
Perhaps you could use a jack and / or boards to raise the low side of the loader or perhaps you could remove some dirt where one wheel of the tractor goes to get it level with respect to the loader.