I was trying to figure this out myself tonight. Here’s what I came up with:
In style.css, under Main Content, you’ll need something like the following:
#content .post,
#content .page{
overflow:hidden;
margin-bottom:15px;
width: 930px;
}
Adding a width of 930px or so will spread your content over the full width, but you’re right that that will effect the home page as well. Here’s how you correct that. Also under Main Content, you’ll need something like this:
#posts-list .post{
overflow:hidden;
padding-bottom: 25px;
margin-bottom:25px;
border-bottom: 1px dotted #3e4348;
padding-top: 25px;
width: 620px !important;
By doing this, I was able to remove the call to sidebar from both my single.php and my page.php and spread the content over the full width, without effecting the home page.