I advocate a norton 4/8 for learning to hone, for a couple of reasons. The first is that it is a known quantity. Every one of them will be the same as the one next to it. With coticules there is a lot of variation. They are all over the spectrum in terms of 'grit', speed, and hardness. This can make it harder to learn to use it properly. And in the past, you could argue that coticules were cheaper. But that is way in the past. A mid sized coticule is already as expensive as a much bigger norton.