Good job, Have you heard of Superclamps, they won't scratch your skis, totally adjustable, and lockable. Yes , they will cost more then yours but factor in the time to build yours, it will be about the same cost, we know. you will only have to buy them once and you will own them for the rest of your trailering days. Keep up the good ideas, thats how we started 13 years ago.
used them for the first time over the weekend, nice not to have to crawl up on the 4 place and move sleds back and forth to get the perfect fit with the bolt downs.
Only thing I would do is add a vertical rod at the very front and rear of the inside angle piece. This "tower" of metal would keep the horizontal trap rods from rolling either forward or backward during a jarring motion. Your height adjustment would not be limited, but the potential motion of the skis would be contained quicker.