There is no back panel--it is open in back.
Front is not notched. Here are some more pics.
First pic is the back of the stand.
Next pic is of the front support between the doors and the center brace (you can see the tank on top).
My plan is to just use 1X2 " pine boards-- reinforce 4 corners, and the middle bracing front and back and also just below the side braces (that you can see in the second picture- small piece of wood that the tank bottom trim sits on along with the main wall of the stand).
I figure I will just add this for piece of mind. I know the stand was designed to hold the 120 gallon tank but it just feels light.
Thanks
Greg