>Pat's idea is to apply the shape of the diminished chord, of which
>there are only two practical ones on the guitar for these purposes.
Actually, as I stated earlier in my post, Pat advocates learning the
diminished chords on any and all groups of four strings on the guitar.
The voicings that you can derive from this are of course going to vary
in practicality, but they encompass a greater range of chords than the
drop 2's. BTW, I had never even heard of the terms "drop 2" etc. until I
had been playing for quite some time, even though I'd already done all
these inversions. From what I have heard using these terms (on guitar at
least) stems from Jack Peterson, whose teachings had a great deal to do
with the curricula at Berklee and North Texas State.
Clay