We are building a 52,000lb stellar hooklift on a 4 axle tractor and would like some feed back from other roll off owners on specing the cans. Does anyone use the 40-50 yd smooth exterior wall cans that taper on the bottom and how do they hold up? any info would be apreciated. we are starting with 4ea 20 yd concrete type cans and 4 ea 40 yd debris cans.