In the Riptide descriptions, he has 11 x 11 in spot and 10 7/8 x 10 7/8 in another spot. Which is right?
I suppose carpentry was never an exact science. The common adopted standard is 10 7/8 x 10 7/8 because when you wrap the metal around it, it will add a little. A DDR square panel is suppose to be 11 x 11. So obviously, when you get that metal wrapped around it, your end result should be about this. Of course, if you are not bothering doing the wrapping, then you can just cut straight to 11 x 11.