Maybe it's me, but I'm not seeing the advantage to using them at all? I don't see a listed weight, but I bet they are cast aluminum and not all that light weight. A typical cast wheel is just as heavy if not heavier as a similar sized steel counterpart, especially in the case of heavy weight rated wheel where light weight construction is not paramount. I would think, for your purpose you would be wanting to find the narrowest and lightest wheel possible. I think your best option would be to find a couple of the 16x6.5" Forged PYO wheels off a 01-10 Chevy/GMC 2500hd. They are only 17lbs each. Of course you would need to bore out the center hole to fit the Dodge hub. The narrow width, with some narrow tires would reduce weight, reduce rolling resistance, and help aerodynamics slightly. I believe the 2nd gen Cummins 16" wheels were also forged and pretty lightweight, although they are 16x8 so you have an extra 1.5" of material to add weight, increase rolling resistance, and increase wind resistance. I believe the 17x8 3rd Gen aluminum wheels are around 25lbs each.
Just for the heck of it, I recently weighed some wheels I had sitting around the shop. Stock 16x6.5" steel spare from my 2500HD-28lbs, stock 16x7 cast aluminum wheel from my wife's Infiniti QX4 (nissan pathfinder) 26lbs, stock 16x7 cast aluminum wheel from GMC 1/2 ton truck 23lbs.
I would honestly go with a narrow stock steelie before that wheel unless you are really caring about the looks aspect of it. As far as the legalities/safety of the trailer wheel, I am not sure.
