My interest here is to determine whether I might learn something from studying with Jerome Callet. While I am also interested in other opinions, [even those that relate to his playing ability] I suspect the only people who can offer relevant opinions regarding his teaching are those who have tried it for an extended period and obtained results which they could attribute to the method. [whether positive or negative]
I take as a given that there are differences between a person's ability to perform and that person's ability to teach. However, just because a person does not perform at a high level does not necessarily relate to that person's ability to teach.
Said differently, "Even the dumbest of us can have great ideas."