Adjusting column widths in new Design Studio layout

[wildbug]

Hello, I want to switch to the new NING Design Studio theme 2-column layout but I need to replicate the layout of my integrated WordPress blog. This means I need to create a dark brown background that the whole layout sits on, slightly narrowing the 2 column widths. The overall width of my layout is 955px. The left column is 620px and the right column is 295px. The remainder 40px are in margins between the columns. How can I do this? Here is a snippet from my WordPress site, whose column widths I want to replicate:

[wildbug]

I wonder if there is a particular theme that would make this easier to do than another. Anyone know?

[Robert Lunte]

I am trying to do the same thing as you with Design Studio. I found using Firebug to find the elements helped but i couldn't make the big column bigger. I could make the right column smaller but i couldnt align it. Sorry i know this doesn't answer your question but i just don't understand why these attributes arent in the css and clear.