Bart, I am so happy for you that you have taken the initiative to venture into doing something that is so purely empirical-based. As far as I know, there is not a lot of publicly available and at the same usable literature on the art of tea-blending. Older literature also based on the limited tea varieties available back in the old days. A lot of commercial operations are using additives and non-teas in their blends so there is virtually no rules. That is not to say I endorse that, though.
If you are into it, I encourage you to first get more acquainted first with all the non-blended tea varieties in the world and keep a good log of them. This will be your ingredient book.
Have fun!
