One is GDA, one is C/D and a partial F, one is F, and I am working on a B-flat. The resting one is a GDA and I remember I have my original GDA and one is an unmodified twenty one bar and one is unmodified fifteen bar.

The rest are in various states of experimentation or barless awaiting new finish or some such...I think the chord systems are all in the forum on various autoharp threads.

My original modifications I learned from Bryan and did myself and my subsequent ones are Mark's design. So I just play diatonics...