360 US gallons? for a 1/4 inch thick glass? this is impossible...as for my experience the 1/4 inch glass can only hold a max of 100-120 gallons thats 2x2x4 feet
I would go with how ever long you can go, say for example 6 foot. Then a depth of 2.5 feet and a height of 18" MAX. 6x2.5x1.5 = 168 Gallons. Just an estimate. Make sure you have very good bracing.