[PhilJ]

ok, understood.

You can tweak the .container widths for specific screen widths in a variety of ways like this...

@media only screen and (min-width: 1024px) {
    .container { width: 960px; }
}

@media only screen and (max-width: 1024px) {
    .container { width: 960px; }
}

@media only screen and (min-width: 1024px) and (max-width: 1280px) {
    .container { width: 960px; }
}

Etc.

In v1, you can add the code to the bottom of skin/reboot/css/reboot.css

In v2, media queries are in a separate CSS file.

Screenfly is a useful tool for testing various screen widths / devices.