Yep these are perfect. Had also considered putting together a separate community for books parallel to !opencourselectures@slrpnk.net. The main advantage there is searchability, but that does necessitate that each post relate directly to a book rather than a collection like you've listed here. Also feel free to make a top level post with those links (or if you'd prefer I'd be happy to do it) as that is exactly the sort of content we're looking for.