To answer the weight question. It all depends on your vehicle. Mine, for example, is a straight truck. It weighs about 14k lbs. that leaves me with about 12k lbs to make up my gross weight. I don't put 12 on my truck though. I won't go over 10 b/c it put me over on my steers. The weight distribution will not let me, therefore I'm at 24ft and 10k lbs.
Different setups will allow for more or less weight and length depending on vehicle design, but all must be less than 26k total.
