I've just bought myself the 2nd part of the pink book (I think it's blue? I ordered it online...) and the workbook with the aim of taking G6 theory next year. One of my pupild asked me to teach it her, and after a long chat with the parents, we've decided to learn it together, me a term ahead! I'm a bit dubious, but they won't pay for a different (better) teacher. Apparently I'm a bargain
As to C@W's question, have you done G5 theory? How did you get on with cadences and appropriate chords etc.? It seems to be the next step along that road.