Mmm. . . so 2/3 philosophy will imply not partitioning, I would guess. Narrowing the target will no doubt focus the read-writes on a smaller spot. Never gave that a thought when I put the OS and Office on the first partition, though buying an OS dedicated drive of say, 100 gig, would be as burdened as my 240's half. That's of course if an SSD really hides the other partition from the first.
Book? Same The Perfect Code. Still on Kindle, but now being rewritten with a lot of over-thinking complexity ripped out and the sequel ready to combine to make the full yarn. It would have been done a year ago if life hadn't got in the way. Ho hum.