Help with overflow size.

[lookout888]

so I have searched and can not find the answer. I am going to be ordering a new tank and am trying to get all the dementions figured out. It is going to have a 2' long overflow on the back but I am unsure of how deep and high it should be. I am going to have 3 X 1.5'' drains drilled in the back with just a T on each side ( 2 facing down 1 facing up.... bean drain). There will be uero bracing, still waiting to find out how wide it will be or if i need it on the back.
Here is what I had planned but this is just a guess. Can anyone with an overflow like this chime in and let me know how wide theres is and if they would have liked it wider.. deeper?

Thanks for your time.
188065