If James Campbell is still around, I'd just like to say thanks again for his work on this old post. I think it's only now that I probably fully understand all that was written. It probably doesn't directly help with my beginner efforts to learn Cantonese, but has enabled me to understand the seemingly conflicting tone names/categories that I find in different books. I don't think I would ever have 'cracked the code' to know that Cantonese tones commonly numbered 4, 5, 6 & 9 are described as "lower" because they were on the bottom row of some ancient tone chart. This, and the info provided on mapping between tones, contours, dialects is fascinating, and helps makes sense in a complicated arena.
Regards,
rathpy