There's a lot more work to do on this part yet, but I nearly have the shape down pat to brace the turtle deck tab. I used the 3/8 bullnose mill to drill into the butt joint between the angles and 0.063" brace to make room for the nutplate to fit centrally. Next time I would use the 1/4' bull nose mill to make the hole smaller (to better support the base of the nutplate).