Good question! So believe it or not I actually can't find the cutting diagram on graph paper that I used, but even if I did still have it it was mostly chicken scratch and overlapping lines which would make it very hard to decipher. Looking back on using 4 sheets, once I was done I had literally less than a square foot of scrap wood. Every single cut had to be exact and this limited supply actually made me do the braces as 5 inches instead of 6 like I wanted. So without actually getting out some graph paper and drawing up a diagram, my recommendation would be to use 5 sheets of plywood. This might be frustrating as that an extra 20-40$ depending on where you live, but in the grand scheme of things, using an extra sheet probably would have saved me hours of cutting and planning and also added to the security of the tank. It CAN be done in 4 sheets, but that money saved becomes nothing once you start comparing what could happen if you mess up and your tank fails. Not buying an extra sheet and getting my exact dimensions is one of the few things I would change about this tank if I had to do it over. Hope this helps!