At first, I just loaded it by adding a <script>-tag to the page with jQuery, and wait till it came available. In the end, this doesn't work because it could take .1 or .2 seconds extra to load. It wasn't really noticable at the start, and it was 1 time per page, but still it's better to fetch it directly.
Then I found out about @Require, which loads the file along with the script when installing, and so it doesn't cost any extra time. So I was satisfied with the result (except that 1 person complained about fetching things from google, the script is hosted there etc.).
After that, 2 problems came up: jQuery 1.4 came out, which did not work fully in greasemonkey, and I tried to make the script work in Chrome, which does not support @Require.
The solution for the latter was to include the jQuery-code in the script itself. It's ugly, but happily it's not too large after minification (script is still smaller now than when I started), and it doesn't complicate anything after that.
The other was to adapt the jQuery code in a specific place.. I chose not to get stuck with an old version, so I get the code, make the modifications and minify it through google closure. With jQuery 1.4.4, there seem to be 3 places the code has to be adjusted now, and I'm wondering if the speedup that came with 1.4 and 1.4.2 is worth making the changes.. In time, I hope a better solution will show up.