The drive the iBook Chamshell came with was too small to put Mac OS X on it. I have used it with Mac OS 9.2.2, until the internet browsers were obsolute.
The repair went well. I only had a bit of trouble with the clutch cover on reinstall. I also forgot the 5mm nut driver for the stand offs, but a pair of small piers did the trick.
The instructions and the hard drive replacement were excellent. I suggest that you find a fish lure or bead holder to put the screws into. This separates them and you won't lose them on the re-install.