Not only is setting custom rules inordinately difficult, but when I added a new rule, following the documentation, it blocked and overwrote every single tab I had open, (none of which had anything to do with the content of the rule I had written, most of them minimized). Seemingly arbitrarily, this add-on rarely preserves the URL of the site it had just blocked, making it essentially impossible to meaningfully recover anything.
The detour of trying to scan through my history, retracing links and searches to figure out which tabs were for which project and reorganize them is not something that I wanted to do, especially with nothing to show for it.