I have Campbell, the Patter Manual and the OnTrack notes. Both the former are interesting and extremely useful reading and will be a great benefit. I instruct part-time though, so the only way I can ensure decent personal standardisation after a long period away is to brief directly from a set of notes and IMHO the OnTrack notes are as good as a non-CFS person is ever likely to come across.
I'm not linked with them in any way but I'm happy to recommend their paperwork.