almost there!
you have the drain and siphon sizes reverse, siphon should be bigger than the drain.
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I know you're planning teeth, but they're hard to draw!
about the teeth:
you will want to cut straining "teeth" into your internal box (1/4 inch is a popular size, spaced 1/4 inch apart), you want the bottom of the "teeth" to be at or below the same level as your outside weir ... this will ensure most efficient operation and minimize build up of debris inside the overflow
the tops of the teeth should come out of the water somewhat as well, to help prevent debris from "falling over" the edge and getting stuck in a siphon