You may find
this writeup useful for the 300ZX.
As regards the angle: this console was about 20 degrees. What that means is that the drive tray inside the player is no longer horizontal. 16 degrees was determined by the size of the drives and tray inside the player (due to the DIN case size), and common installation angles in consoles. The drive tray hangs by 4 rubber, conical shock mounts. These are designed to work in tension, vertically. If you mount the player so that the tray is no longer horizontal, then the tray "swings" back and forward, instead of up and down, inside the player. Hence, on a large shock, the tray tends to knife forwards against the display cable, and back against the power and audio harness. The shock rating of the drive assumes vertical shock, so if a shock occurs off-axis, then you've no idea what damage will occur to the drive, which could in the end shorten drive life.
You shouldn't be too worried about being slightly off 16 degrees: experience seems to show that it doesn't affect drive life too much - for example, my own Mk 1 is mounted horizontally (therefore putting the drives at a -16 degree angle) in a Mini - and despite two crashes, a broken wheel rim in a pothole, and the standard suspension quality of the Mini (ie., none whatsoever) the drives are the original ones, and seem to be in good order after some 4 years' use. If you mounted vertically so that the shock mounts are effectively useless, then yes, I would worry
Maybe you should mail ANdrew (the owner of the ZX in the install I did with him) to see what his experiences have been.