I've been given a windows machine so trying winuae and the overscan is totally different
looks like i'm stuck with 640 as the amos screen won't shift left, fs-uae has an auto-zoom effect which is doing the nice overscan!
but I've found out that WinUAE and FS-UAE are actually quite different in other ways, and something wonderful has happened to the "memory" bugs I was getting in fxbox - it doesn't guru in winuae
when the memory gets fragged you just can't allocate it, which is fine. but in fs-uae it will guru the amiga - interesting.
next chance I get (don't get much time on this any more...) I'm going to delve into the amos.library to see where the screen data is set and hack a way to move the display offset...