This was very informative. Im in the process of designing a plywood build with almost identical dimensions to your 720 gallon. Im also going with 3/4" glass and just had a question about the install. Do you have a lip/ledge of wood for the bottom edge of the glass to sit on? or is the silicone strong enough to keep the glass in place after flipping the tank upright?
Since I installed the 1/2" PVC bottom on the 720 gallon tank the glass was butted against that bottom. If you are using RTV 108 to seal the glass in place it will not go anywhere. On my reef tank the glass only has a could of small shims of PVC to separate it from the bottom. RTV 108 is strong enough to hold it in place on its own but a couple of shims are a good idea to take that load off of the seal. I gave my tank 2 weeks to cure the glass once it was sealed. I know it was overkill but it worked. I did leave a 2x4 brace in place for a week or two when I flipped the tank just in case it somehow did not seal properly.