Here is just a thought to anyone looking for a good quality foam- I recycled some of my sons old kids furniture to make the cushions for my
Scamp. He had a loveseat, all made of foam that unfolded into a full size mattress. It was high density 5" foam and he had outgrown it so I put it to good use. He also had a small flip chair made of the same stuff so between the two of them, I was able to get all of my cushions done. If you check out my pics of the front bed, you will see that I have a great bed that with some memory foam on top is a full 7" thick! Like I said, just an idea of you have such things kicking around, or come upon them at a yard sale or something. OH- and ditto on cutting the foam with the electric knife- its the ONLY way to go!