I see where you are coming from and your way of figuring gallons per plant makes sense and is a better way to document the source.
The big difference is I figured 100 sq-ft per plant which was my guesstimate and you figured 30 sg-ft per plant. The UF I quoted from says "Commercially, plant spacings of 8 ft x 8 ft (2.4 m x 2.4 m) to 11 ft x 11 ft (3.4 m x 3.4 m) result in 360 to 680 plants per acre for this part of the world. That is around say 70 sq-ft per plant.
Here is the link.
http://aggie-horticulture.tamu.edu/s...nasFlorida.pdf