well i started messing around with it the other day and besides going the next big step and taking it apart to drill other holes (too much for me) i simply put cds on the very bottom then lay a shelf on top of them then dvds then work up with the holes then. it ends up fine and looking way better than what i had it.

So I finally needed to get rid of the bottom two rows of CDs on my shelf and ran into the extra six inches of space problem you were talking about. The only practical way that I could arrrange the shelves without having too much wasted space was to split the lower section of the rack unit into four shelves, three for DVDs and one for CDs. I ended up having to buy some support brackets to customize the height of the bottom shelf as the predrilled holes didn't go down far enough for me to accomplish the correct arrangement. I didn't want to risk ruining the unit, so I installed these without drilling pilot holes for the screws.

Heres a pic of the extra brackets I installed just below the last set of predrilled holes:

And here's how the shelf looks with the bottom shelf inserted and filled with DVDs and CDs:

My titles are packed fairly tightly and I use re-sealable sleeves for most of my cases....which help protect from scuffs and rips. I've been using this system for a few years with zero damage to either cases or discs. I can't stand having loosey goosey dvds tipped over this way and that way....it just looks like shit. Mine looks like an actual library....just with nothing checked out.