Red John Smiley_X01
For Firefox Version 19.0
In my browser only works:
Header in px: 1366 x 107
Footer in px: 1366 x 46
So I rescaled it to 2553 x 200 (Header) and 2970 x 100 (Footer).
And it still works but when I create a new persona with the same porportion it don't work anymore.
Download PixelRuler (Freeware) to create your own optimal persona.
It helped me to find out the optimal width and height for my browser.
FYI: You're right, english is not my first language.