As Ron G. points out, you are maxing out most of your ratings, but he does not point out your payload capacity problem.
By your own figures in the first post, you only have 800 lbs of payload capacity left over for the trailer's tongue weight. In the first "assumed" set up, you will be over the payload capacity and in the second, just under the payload capacity. So obviously, the 2nd set up would be a better choice.
However, you are very close to maxing out just about every rating of the tow vehicle. Don't you think that it will definitely have a long term negative effect on the tow vehicle...not to mention the driver (you?).
Now I realize that Ron G. is one of our expert seniors here who regularly posts facts rather than possibilities and can back them up with math....however, I never have been a real proponent of the 25% of the tongue weight being transferred back to the trailer as I never found that to be true when I had my TT with the Dual Cam system and also the Hensley Arrow. Maybe I just didn't have it adjusted corectly. I know it does transfers some (maybe 25%..I don't know) to the front tires of the tow vehicle, but 25% back to the trailer? I will defer to his expert knowledge, but will keep my doubts.
In any case, I still propose that you go with something that is lighter and not exceed 80% of the max ratings. It only makes good sense.
Good luck
Ron L.