`-l` is *not* a workaround since the search criteria (available in `find`) are the main point.
Instead of another message tab I would rather envision it as a kind of a a clone of the existing `grep` dialog (i.e. launchable via the edit menu) with the opportunity to enrich it even more like `mate-search-tool` (not required by me at all but this would increase usability for people not familiar with `find`, cf. https://windywindycitytech.files.wordpress.com/2013/01/screenshot-search2bfo...)
In #54 the OP waited for answers to his questions before abandoning it mentally ;)