Would it help that these aren't the cheap-ass ones sold on Amazon? Plus I'm kind of banking on being able to assemble this in a way where I could disassemble it without removing the books so if I needed to pack everything up I'd just need to cut the zip ties or unscrew whatever's holding them in one place (carefully, obviously) and then just stuff the spaces with bubble wrap (I'd probably put some kind of foam towards the back before putting the books in) and wrap each crate in bubble wrap and plastic. Naturally a major problem comes from the scenario where I don't have a U-Haul and have to ship each crate.
I was going to put it against the wall that separates the left side of my bed and the bathroom, but this shelf would be longer that the wall it'd be against and there'd be a roughly 1" gap in the back. Plus the wall is just a sheet of plywood so I'd have to find some other way of making sure it can't tip over.
As for milk crate bookshelves:
This looks to be the closest to what I'm trying to make, except with mine I'd have it as one unit, not two.
Would putting the heavy stuff on the bottom shelves mitigate the issue of putting too much weight on the top of the bottom shelves? Would putting something between each row to absorb a lot of the shock?