David, I agree about this "obsession with the #4", and that Paul "has much sound advice and some that is dreadful".
One must keep in mind that everyone has preferred ways of doing this, be they sharpening, joinery or jointing. It is the openness to this that, in my opinion, differentiates a great teacher from a good one. I am mindful of a professor of mine, Dreyer Kruger, when I was in psychology graduate school in the late 70's: A lady in her late 60s arrived for an appointment with him to discuss the possibility of researching a Master's degree. When she told him that the topic was levitation, he leaned back in his chair to reflect for a while. Finally he said to her, "Well Isaac Newton has been around 300 years. It's time for a change". And she received permission to go ahead. I loved his sense of humour and flexible attitude to life.
Regards from Perth
Derek