So what I've done at the moment is applied it to my journal as a secondary style, and I have included links from my comments page to 'Unthread comments', so that the links reload the comments page in the chronological version of his layout. This is kind of a crude kludge for the time being; what I'd really like to do is adapt his code to my layout directly. But obviously the latter is more work, especially for a clueless non-programmer like me. So if you read my journal directly rather than on your friends page, you can use this feature if you like.
If you want to apply it to your own journal it's a bit of a complicated process, but I can explain how I went about it. You need a paid account to be able to do it, though of course if cmshaw wins the competition his style may become public and thus potentially available to free users.
Also, I pointed out to cmshaw some potential usability issues with his layout as it is, and offered to modify it to make it more customizable by adding more named CSS classes to the HTML it generates. And he was very receptive to my ideas. So I feel all Open Source-ish now; I wish I knew what I was doing more!