Is there a way to make my posted books that are on hold match my TBR list? I've noticed that the latter has more titles, and I'm persnickety enough that I want them to match, especially because sometimes I'll use my hold list to decide what to read next, and will re-post whatever I've read from there too. (But sometimes I'll do the same with TBR.)

Similarly, if I remove a hold from a posted book from my bookshelf, does it automatically update my TBR, and vice versa?

First open the lists (bookshelf books on hold/ TBR pile) in different windows so you can look at them both at the same time, and sort both lists the same way -- I'd suggest to sort it by title in this case.  Then, since your TBR is longer, you can put your bookshelf on vacation hold (so you don't accidentally post a WL book) and go through your TBR.  Any time you find a book that's not on your bookshelf, post it.  Double check the ISBN, title, author and book type as you post.

If you find any books on your bookshelf that aren't on your TBR, click on the title, then on "more options" --> "+ TBR pile." 

When your numbers match, go to your bookshelf, and, still looking at your "hold" books, sort it by "date --> descending."  All the books you just posted will be at the top, so put them on individual hold.  Then take your bookshelf off vacation hold.

I don't use that hold feature on my bookshelf at all, just click "no" when it asks if I want to add to my bookshelf but "yes" to 'add to TBR.' I post books directly from the TBR when I'm done with them, as it is a full and accurate list of what I have in my home that I have not yet read. I have added books to my TBR list that I purchase, receive as gifts, etc. too, not just books I've received from PBS, so this way I can find them all there in one place.

Cheryl

I don't put them on bookshelf on hold either. Too easy to accidentally unhold one you aren't ready to send. 

I repost books with the book in my hand by the ISBN on the back.  I've been surprised a few times by the one I received not actually being the ISBN I requested.  It makes no difference to me because I just want to read it and pass it on but it's  a big deal to some people.  It also puts the book in my hand to double check it's postability.