Corsair Obsidian 350D ODD bay depth

I'm reading about some issues some people have installing their bluray drive or other in the 5.25" bays of the 350D, and I am wondering just how much depth there is to these until one hits the mobo?



I intend to stealth mine, and this would possibly mean going a bit deeper still..

My Lite On HES112 is 170mm or 6" 3/4ths deep..