...I just felt the bulk of the ebook was mostly "fluff"
Isn't this the case with most books claiming to "teach" people Sudoku, which are padded out with actual puzzles with very little meaty commentary? I feel that what people with, say, six months' experience need is not only a good summary of the established techniques, such as Angusj and Simes provide online (and which this forum's experienced practitioners do a marvellous job in explaining), but also a set of puzzles at the Times "Fiendish" or Sunday Times level, with a detailed commentary on how the solution is reached. For me this would ideally be without the use of pencil-marks, or with only limited use of them. Personally, I think that what many solvers are trying to achieve is to be able to do a Fiendish regularly in half-an-hour. There are lots of books of this type dealing with cryptic crosswords of the Times level, so why not one for Sudoku? Maybe a collaborative venture by members of this Forum, with Wayne (with his new-found leisure?
or
?) as Editor?