I generally just look up the specs at each MFGs site that I am interested in.
Weight generally is not an issue with ATs. Maybe a Pound or two either way.
Size is generally pretty close to sidewall spec. Many tires are actually 1/4" to 1/2" Undersized, except INTERCO and BFG.
It may be useful, but would take a lot of leg work and constant updating.
I remember seeing an article in one of the offroad magazines a while back where they did a comparo of a heavy versus a light set of wheels and tires. It made a big difference. They chose the Duratrac for the "light" tire, and since i love mine in 33" i figured i'd mention it