That is the most TW I have ever heard on a Bumper Pull Toy Hauler. I think I would have went with the lower TW and then figured out why the trailer was not handling well. Anti sway, stiffer tires truck tires suspension??? 1700lbs TW on a 13000lb trailer with triple axles should be plenty...
What did they do to the frame of your trailer to make it stronger? Looking at the example of ependy pics I would think they would have to reinforce the entire frame structure.
They make super heavy rated trailer hitches but if your hitch is stock on your Ford I would guess it's more like 1250TW and 12,500 Gross..Good luck...