The P bass body is the most comfortable one ever made, for me, so it's hard for me to wrap my head around this one. Always play standing up--problem solved!
Yeah-I know, I should play with a strap both seated and standing and the bass position should be constant......and while I'm at it I'll get 8 hrs of sleep per night, not drink, drop the cigars and learn Latin in my copious free time
For me, any body shape is fine when standing. When seated, however, bringing my plucking hand back and draping my 4arm over the upper body edge cause severe problems for my rt shoulder. The closer the G string is to my thigh and the closer the upper body edge is to the B, the better for me. Std P and J bodies don't help me out much in that regard. The 55-64 shape is great, though, because the G is very close to the lower edge of the body.

