You're correct Ian that the naming is a bit unnecessary as I too think of them as 0,A,B,C,1,2....etc. I just did it because the pic of Cowboys copedent shows them as P1, P2, P3, etc.
Cowboy says he gets a lot of his unique sounds from the P0 and I'm guessing that's why its there. There's a small discussion on it that I started here:
http://bb.steelguitarforum.com/viewtopi ... eddie+long
I didn't put Cowboy's P8 on there because the BMI guys and Cowboy himself told me he never uses it.
I'm not sure how he uses P7. Standard C6 P4 raises strings 3 & 7 a whole tone to B, while Cowboys P7 raises 4 & 8 a 1/2 tone to Bb. They look similar but, I'm unsure. My theory is weak.
I hope to one day sit down to a few lessons with Cowboy himself once I am more comfortable with the basics of C6.