Boomerang, you might want to give a look to this thread and the data that was collected. It's all real world scale results as opposed to estimates. As to your truck, that's up to you.
http://www.5thwheelforums.com/forums...153&highlight=
As I said before contact the factory and ask them for the estimated weight for your rig as ordered. They can't give you the scale weight until it's built but they should be able to give you a reasonable ball park, assuming that they do in fact weigh each rig as it leaves the factory.