How many holes is too many?

the number of holes will be based on how close the holes are to each other along with the thickness of the glass, all measurements are from the outside of the hole not the center, heres the formula for minimum distance:

x = 1.5 t
y = 4 t
t= thickness of glass

single hole: x from edge

single hole near corner: x first edge, y second edge

side by side holes: x from edge, 4 t apart

side by side holes near corner: x first edge, y second edge, 4 t apart

 

I have 2 holes in each corner overflow but only one is currently being used in each overflow. There is one extra in each overflow for future use.

There are 6 outside of the overflows. 2 for closed loop pickup and 4 for closed loop return. I believe there may be some pictures somewhere on my thread.