I'd refer anyone curious about 4th position to my post on 5/1/10, "4th position, a blues overview". I think 4th may be the most under-used practical blues position out there right now. I'd back that up with two SPAH anectdotes. At the Sacramento convention I used it in the jam circle. Mark Hummel was in the circle at that time. When Mark was leaving the convention, Rupert Oysler asked him if anyone's playing had caught his attention during the previous night's jam. Mark told him somebody a few chairs down had intrigued him because he couldn't figure out the position being used. After a few questions, Rupert figured out it was me. I was playing standard Jr. Wells licks, but playing them in the key of A on a C harp. At a Jimi Lee hallway jam the following year, I played a solo in E on a G harp. Jimi stopped the jam on the spot, and asked me what harp I had just used. He loved the sound of it. Neither of these two incidents were minor key tunes. They were major key, standard blues that everyone else was using a cross harp on. It just required a couple of bends to make this "minor" position sound "major".
Mick Zaklan