Notching glass for external overflow

[Trevor W]

Just curious if anyone has notched a pane of glass for an external overflow using a dremel. If so any tips or advice?

Also I know that the depth of the notch will determine the height of the water but how high will the water rise above the bottom of the notch when you put some 1/4" spaced acrylic teeth infront of it. Hope that isn't a dumb question hahaha