The second option you provided worked out best for me, so thanks for that... I really appreciate it. The third one didn't let me add more than 2 tags; not sure it was supposed to or not.
One more question for you...
Code:
{#status:}{:'uppercase(list_item(list_intersection(field("tag"),sublist("Mystery,Science Fiction",0,0,","), ","),0,","))'| - |}
Is it possible to have it leave the column blank if no tags are found? It's only 2 extra shelves (all read books and all unread books), so not a big deal if it can't; I'm just a minimalist and don't like things I don't need.
Thanks again!