I suggest you don't make your cutout any taller than 24".
Heres a safety factor break down.
1.8 >= should hold water (excessive bowing)
1.9 to 2.1 Will hold water, but don't look at it funny, because it might break (excessive bowing).
2.2 to 2.4 should handle light knocks from pets inside (medium bowing)
2.5 to 2.6 should handle bumps from inside and out. (Low - medium bowing)
2.7 And up monster fish (up to 16") resistant. (Low bowing)
3 and up Kid resistant (bowing hardly noticeable)
24" height gives you a safety factor of 2.4.
25" gives you 2.1.
23" will give you 2.7. And this is what I suggest you use.
The heights used to do the calcs refer to the amount of glass submerged in the water.
Use it, don't use it. But you have the facts now.
what about making the tank 96"wideX26"highX20"deep. doing a cutout that is 93"x23"..? and what would i need to do to my floors to safely support that amount of weight?