I used to use those with my Expedition, towing my 20 and 24 foot enclosed trailers. Takes a minute per side to install and take off, work great.
As for enclosed trailers, if all you are going to haul is the "7", you might consider a low roof 16 footer designed for the motorcycle crowd. A lot of the Cobra replica guys use them.
In regards to brake bias on a trailer, get yourself an adjustable (digital) controller. Weight distribution hitch will be a must for an enclosed trailer, and I suggest you opt for the anti sway bar as well. I never town anything enclosed without those three items. Even my featherlite open trailer I use a digital brake controller.......
Bill S.