Looks like a nice trailer with galvanized frame, LED lights, and torsion axles.
The 2011 GTI155 is like 650 lbs dry. Modern GTI155s are pushing 790 lbs.
And if you add 15 gallons of gas, that is another 100 lbs
It would probably be fine to carry the 2011 GTI155.
They claim their trailers are designed to "carry" up to 1200 lbs. So hopefully that means the "capacity" number of 1000 lbs in the spec sheet is the payload rating. Normally, trailers are specified by their axle or gross weight rating, not payload, so it would be worth clarifying.
I personally would go with the WV1200 for a little extra weight margin and in case you get a newer, heavier PWC someday.