Full screen, for me, isn't as useful for a variety of reasons.
I can see it's be calculated in many places, I just haven't been able to pin down which one controls the size on sit_screen.php These types of calculations are all over the php pages, but I've changed quite a few without changing anything.
I did see some references to screen size calculations. Now I need to find them again and look at that further based on what you've mentioned here.
mapWidth = viewportwidth * .35;
mapHeight = viewportheight * .50;
rightcolwidth = outerwidth * .35;
rightcolheight = outerheight * .75;