Not enough room for TinyMCE

The way I have it configured, tinyMCE requires about 600px width. But the only pages where the content area is wide enough are the admin pages, thanks to the otherwise extremely useful burnt_is_admin function. Now, my PHP savvy is too small to even attempt to create a function that covers the add pages. Would it be possible to add an add function to template.php, and page_tpl.php probably an add class to style.css?