I took a look at it. I think it's a bit too small. Especially for 4 people. I'm not opposed to a folding tri, I just think it gets a bit more complicated to build and the windrider 17 doesn't solve much of the issues a regular beach cat has - limited comfort and wet.
I haven't looked hard at any of the folding tri plans. I had kinda thrown them out as probably being too expensive. I'm not sure how the cost to build compares. Also I don't see many that aren't designed with a big cabin. I really don't need or want a lot of cabin space.