Is there anyway to know where you are in the FIFO line???  I know that if I had put the book on my RL I could see how many there are in the system, and then when I posted them I should be the next person.  I don't want to unpost all my books.  If there are 300 copies of something and I am #299 I think I would rather take my book and donate it somewhere. 

Adding the book to your RL is currently the only way to know how many there are in the system.  However, if you have had a book on your shelf since you joined, adding it to your RL will not be helpful in determining where you are in FIFO...you may be in the middle or even the front, depending on how popular the book is. 

Yes, your reminder list shows how many copies of a book are available in the system, but if you add a wishlisted book to your reminder list, it is removed from your wishlist, so you lose your place in line.  As Lisa said, there's no current way to figure out where you are in the line, but I wouldn't be surprised if they added that feature here some day. 

YOu can tell where you are in line with a WL book by hovering on the ! by the book on your WL.  There is no way to tell where you are in the FIFO line for a book posted.  You can kind of guestimate if you add it to your RL when you join and then monitor it regularly. But who wants to do that?  I have a bunch of unread books.  Every so often I take one or 2 and see how many are in the system. If there's a whole lot of them, I post them. Then they're working their way up the FIFO while in my TBR pile. I never have more than 1 or 2 on the shelf like that.  Because sometimes they get asked for in a BOX or ordered right off my shelf.  I read fast though so it hasn't been a problem. Most I read before their ordered.

If you don't have the place to store them then donate them to a thrift store or sell them to a UBS.  YOu could try running a 2 for 1, 3 for 1 type deal.  Then you can earn some credits.  Most of the time the shipping doesn't even go up that much for adding an extra book or 2.