Like pullpan said, when those pull type scrapers dig in, they really pull down on the drawbar and rear end of the tractor and lift the front up, so you want as much weight as possible in the front. As far as just hooking it to a tandem rear axled artic, that would be hard on the tires, you typically want to turn a loaded ADT as little as possible because of the strain it puts on the tires.
I personally wonder how good the view is of the front bowl on these Volvo's, there's a lot of tractor from the cab to that first bowl. :beatsme