Your trailer has a 2 1/4" nominal jack post opening. Some jacks can be bought with a 2" post, some with a 2 1/4" post. The mounting plate bolt pattern is the same for both. You can put a 2" in either opening, but, if you buy a jack with a 2 1/4" post, you best have a 2 1/4" opening
Really though, I've installed a 2 1/4" post in a 2" opening. About 10 minutes of work with a grinding cone chucked up in a drill will open the 2" hole up to 2 1/4" easily (you are only taking 1/8" off around the circumference; 2x1/8"=1/4").
Your trailer will take any jack out there, but, I would recommend that you get, at minimum, a 3500 lb rated jack. It doesn't hurt, with power jacks, to have too much lifting ability, particularly with WDH systems as you not only need to lift the tongue weight, but, a substantial weight portion of the rear end of your tow vehicle.
On my 210WBS, that I towed "heavy"; right at the 6000 lb limit), I used an Ultra-Fab 3500 jack with the adjustable foot.
UltraFab 3500 Jack with Adjustable Foot
It was more than enough jack to lift the tongue and the rear end of my 6000 lb Jeep Commander. After the first year, I discarded the adjustable foot on it and installed the Fastway Flip Foot in its place.
Fastway Flip Foot It drops and raises automatically to give you an extra 6" of length eliminating running the jack down so far (slow) or having to put blocks under the foot (aggravating at times).
If you have the option, get a 2 1/4" jack (beefier post), longest "reach" (some can be had in 24" length of lift; coupled with a 6" Fastway you'll have ~30" of "reach"). Any of the major brands are good; everybody has their personal favorites, but, it really boils down to the head size and design. An electric jack isn't rocket science...a 12v motor that spins a standard acme screw shaft jack post.
Installation is a snap with two caveats: make sure that you have good metal to metal (sand the paint off both parts) contact where the jack bolts to the trailer tongue as that is the ground connection for the power path. The second is to make sure that the fuse in the power cable is protected from the elements. A lot of folks have trouble with their jacks and blame the jack when most of the time the problems can be traced back to a bad ground (where the jack bolts to the frame) or a bad fuse connection (corrosion inside the fuse holder). Another good recommendation is a cover for the power head. While they are
supposed to be weatherproof, most will leak over time, particularly in a driving rain while going down the road. Some folks put a small bucket over the head, while some, like me, used a waterproof black bag with drawstring pulled up tight over the head. With the waterproof bag, I could operated the up/down toggle through the bag and didn't have to take it off unless hooking or unhooking in the dark and I needed the lights.
So any jack will fit your trailer, pick a 3500 lb or higher model, pick the longest shaft you can get, get the adjustable foot model if you don't plan on getting the Fastway Flip Foot. Piece of cake and you'll find that after using it, you'll wonder why anybody wouldn't get one
