Well, it really is gratifying to read all those positive comments. I'll try to help where I can.
A few people asked about levels of difficulty. With every book I do I try to cover pieces for all levels. I do expect people who use my books to have some ukulele experience, such as strumming a few chords. So, they are not for complete beginners. And they are not tutor books, so I don't discuss how to hold the instrument, tuning it, etc. At the other end of the scale there are technically difficult moves in high positions.
There are two technical books - 20 Easy Fingerstyle Studies and 20 Progressive Fingerstyle Studies. These were created not to just increase your technical ability but to equally improve your musicianship, reading ability (including tab), awareness of odd time accents and developed harmonies. Some times these pieces have simple right hand arpeggios so that the attention can be given to the left hand, or vice versa. I also include some fun pieces - blues, even a 12-tone serial piece where you have to make up your own rhythms.
The Sanz book is popular, and I enjoyed doing it. It does contain a couple of hard pieces, such as the famous Canarios, which is difficult on the soprano uke, but a bit easier on the concert or tenor.
Tuning of the banjo-uke - I think I might be a tone lower. The banjo-uke does not sound great, in my opinion, for fingerstyle unless it is tuned a bit lower. I guess I didn't envisage people playing along. My mistake. But you can at least hear the tunes, which, by the way, are great fun to play - among my favourites.
Impossible to rank my books in order of difficulty, as they all cover different levels.
I have no intention of recording a CD for the Scottish Enlightenment book - a guitar book. Maybe some day, as there are some really nice pieces in there.
The latest book is the Bach duets for gCEA tuning on the top part, and DGBE tuning on the bottom part. There are two solo pieces in it, but I often play the top part of the other pieces on my own, and enjoy doing so. I'm really chuffed with this book, and the recording, I think, could stand alone.
Any more questions, just ask.