Tiga theme and comments appearance

I’ve installed the Tiga theme, done a lot of fiddling with it (going totally tacky for Xmas <G> – but would like to use a closer-to-the-original version of this theme after that if I can), and have it almost doing what I want it to do. The main problems I’m finding are to do with the appearance of comments. The comments display is too wide – it’s bad enough when there is no maximum page width set, but when I set it smaller (which is what I want to do), half the comments disappear behind the sidebars.

I’ve hunted through the “Tigarator” settings, comments.php, index.php, single.php, style.css and more, but nothing I can find makes any difference to the width.

As well, I’ve been using Brian’s Threaded Comments, and would prefer to continue using that rather than numbering comments as Tiga does.

The blog is at notsheep.net; if anyone can offer suggestions on either of these two issues, I’d be grateful.