Let's Discuss--Bookcase Shelves

It's time for another round of Jessica Rants! Lol! I've been wanting to rearrange the books in one of my bookcases, but in order to do that I need to move the shelves around so that I can get them set to make it so that there's room for all books to stand normally...but that's not possible when there's a built-in shelf on the bookcase.

Bookcase Shelves

I mean, structurally I can understand if a bookcase NEEDS a shelf to be irremovable...but then of course I still question it. I mean really? The shelf has to be RIGHT THERE and never ever EVER move again EVER?!

It makes it EXTREMELY difficult to set the shelves to be able to hold all tall standing books! And in this instance I'm referring to my Caraval case.

See that shelf right there in the middle? The one that my copies of Finale sits on? It can't be removed or height adjusted, which makes trying to place ALL the other shelves at equal height nearly impossible! I'm trying to figure out if I need to just remove a shelf altogether--which I am loathe to do!--or bring down the second shelf so that the middle shelf has small space that I could put all the decorative art pieces on. They wouldn't all fit of course, but then I realize that only solves half the problem as the lower half will still have no space for a tall book to stand on. 

Plus by shelving them horizontally I feel like I am not getting enough books in. And I worry if the weight distribution is level enough. These are the problems of a bookworm!

I really don't want to remove a shelf because then what do I do with it? It was a pricey book case and I'd like to use all the shelves. Should I just leave it the way it is? I mean...and I shudder to even say it, but should I mix them up? GASP! I love having them grouped together by book! I mean, yes, eventually Caraval might run out of room and overflow into Legendary...which then presents the problem of trying to keep the books all together still. Like should I stack Legendary copies beneath the overflow copies of Caraval?

Does anyone have any advice? If you have a bookcase like this with adjustable shelves except for one that likes to be evil and stable and disrupt the balance of all that is holy and bookish, how do you arrange the shelves? Comments and tips are much appreciated!