My understanding is your load is comfortably under 7000#. With a 12K trailer you have a good amount of head-room. A 10400# should even be fine and you might consider the cost difference between that and a 12K. Many of the "10K" or "9990#" trailers you see are able to be titled at 10400.Thanks for the numbers. I was looking at a 20' and it weighs in at 2750lbs, so I think a 10k is too close for comfort. I may go with a 12k or even a 14k.
you want 10-15% of the total weight behind you in tongue weight.
If you wind up with to much sag in the rear of your tow vehical with that much tongue weight, thats why they made WDH. But even with a WDH you still want 10-15% tongue weight. and adjust the WDH so that your rear bumper height is "correct" (see a setup vid on youtube)