The following tutorial covers changing of Twirl Plone Theme columns width on a Plone 4.2 website.
Content area on a site with Twirl Theme installed is subdivided into three columns: column one and two are the usual portlet columns with content area between them.
You can change the width of the columns in Twirl Diazo Plone Theme via Site Setup -> Diazo Theme -> Advanced Settings tab.
Note: For Diazo Support extension starting with 1.1b1 version, proceed to Site Setup ->Theming -> Advanced Settings tab.
In Parameter expressions textarea change the columnonewidth or/and columntwowidth parameters respectively.
Let's have 150px for the left column and 240px - for the right:
