I am a 5th wheel want-a be! I would like some advice on the 5th wheel towing capacity for the rig we are thinking of buying.We brought a 2010 Chevy Silverado 2500HD Crew Cab, 4x4, 6'6'' box, Duramax Diesel 6.6L V8 turbo, Allison transmission, 3.73 ax...