My P bass is strung with LaBella Jamerson flats and my fretless J bass is strung with LaBella black tapes. I'm in the same camp with DC Bass about flats on a P. The easiest way I can describe the low end of my P bass is that it's really big. I enjoy the black tapes on my fretless, it's a nice cross of the tone of a flat and round, but the low tension is hard to adjust to. If I'm swapping from my Upright to my P bass during a performance, my right hand adjusts really easily to the P bass, while with the J bass the adjustment to the tapes if really tough (they're really easy to overplay).