Also, you don't want a bunch of loud tools and misc junk bouncing around under your seat, so foam is in order. We did this in the USAF in all of our flightline toolboxes, so I learned how already. Basically, starts off for maximum depth by using a 1/4" black rubber mat on the bottom of the drawer, followed by 1 inch black foam pieces the dimension of the drawer until you get to the height you want. 1 inch or anything that gets you there in steps. One large piece is harder to cut in abstract ways depending on the shape of your stuff. I found it easier to use a combination of Xacto knives and an electric carving knife for the bigger stuff. After I have the entire drawer organized, I use 3M spray glue to stick everything together. Fun stuff and teaches you patience!
