overflowContainer strategy for different screens

I have a general problem with the height of overflowContainers.

Usually, I have a kind of header on my bsp page with a fixed height, while the rest of the screen is available for the accplication data itself.

If I want an overflowContainer to be as big as the remaining screen without the header, i don't know how to set the height.

If I set a fixed height, I can only optimize for a certain screen resolution.

On the other side, if I set height="x%", I don't know how many percent of the screen the header takes.

What could I do?