Brettski, I had a floating barley straw crib very similar to this setup with two inch nylon squares. Once I gave up on the barley straw idea (another subject for another time) I added four legs about 25% of the distance in from each end the same way you did and planted it.It took two seasons to get some good growth but found that the weight sagged the center down to the pond floor approx 18 inches, I made mine out of 2 inch schedule 40 and wish I would of added one more leg dead center for a total of five. I cant tell if mine bent or broke but if I do another one will be with 5 legs.
