i have a bx2230. i have a bush hog kk 48". wanted to up grade to a 60" rear finish mower? problem is weight. the 60"rearfm is 660 # . the manual says max is 375. but the 48" bush hog is 400# and the 48" tiller is 525#. both work well . could the 60" rear finish mower be used safly with out...