I apologize for not getting back to you on this!
The value for $min_documentRoot (in the bwp-minify/min/config.php file) is set to whatever the site’s current root directory is (the same as the ABSPATH define is set to), so it varies from site to site as they live in different directories.
You’re right about it working without needing to have the $min_documentRoot for normal WP installs – that’s great! 🙂
However, what I see (with a fresh install of the plugin (v 1.3.3)) is as soon as I hit the save button on the BWP Minify dashboard page (with the “WordPress Document root” (which is what I assume you mean by the custom document root) blank), it still inserts the $min_documentRoot into the config.php file. If you could make sure it doesn’t insert that into the config.php file unless the custom document root is set, that would be really great! 🙂
Thank you!