I read an interview with Lee Sklar once regrding his main axe that has the double reverse P pick up set up. Lee said that he thought the P pick up delivered the ultimate bass tone, but he thought that Leo got the placement all wrong. Just like the OP, Lee said he felt the string balance was way off with the traditional layout and had his bass custom made with two sets in the reverse P layout. Lee also said that bass has probably been used on 90% of all the recordings he has ever done. I actually agree with Lee on this one. I play a lot with a pick and have always found the D & G strings on a P Bass to sound too thin for my likes (same with a Music Man). IMO, a lot of this is technique driven, but with my technique, the reverse P layout offers a more fuller D & G sound.
