Judy, when I make this I put it in a dish that is 35cmx28x5cm and usually make it about 4 layers deep. It is a huge dish of lasagne and does at least 2 meals for 5 of us. I often freeze half of it.
I use my own sauce recipe (which I usually slow cook for some hours) and the cookbook bechamel.
Actually, I think that I had some bechamel left over last tiem, too!
I usually put some fresh parmesan in the bechamel and a mix of parmesan and mozarella on top.