I'm about to begin a series of 5 books, each over 13oz, that are on WLs. Would it be OK to offer all 5 to be sent at once to the same person if I offer them in a certain forum? I had no luck locating the answer in the Help section, but that doesn't mean that it isn't there! They are Christian fiction. I appreciate your help - and patience!

Yes to do this do not put them on your bookshelf.  Make your offer and have them PM you.  Go to their wishlist and post the books directly to their wishlist.

Book Bazaar forum is the place to offer book sets/bundles that you wish to keep together.  As Caroline said, do not post the books individually to your bookshelf, but make arrangements via PM for credits transfer and mailing schedule.

You might also have luck posting this in the Christian Book forum.

You are not supposed to offer WLed books in the Book Bazaar unless they are a boxed set (see the rules there in the red sticky thread at the top of that forum). It seems you can offer them free with an order, but cannot offer WL books there for credits unless they are damaged or a different ISBN than the WLed version.

You CAN offer them in some of the genre forums where they have established WL threads. There are no rules specific to those forums so people started offering them in there to save on postage and get the books sent out to people quickly.