Dear Sheldon, I have seen a P.A. 5 strings with Z3 configuration of pick up on FaceBook, Vip Room Dingwall. The PU were VILLEX, passive. I have always been attracted by Villex, but never had the chance to try one. How does them compare to Your standard FD PU like You put on the Zs? Did You try using silver plated or silver wire for pick ups unstead of usual copper for increasing the conductivity of the wire? (at least on the paper pure silver is better than pure copper, but in my opinion pure silver is not so easy to find...). A side question: I have a 6 string fretless bass provided with a custom pick up that has this problem: the upper 3 strings produce a lower output than the lower 3 strings. inverting the PU of 180 degrees do not change anything: the lower in diameter tha string is, the less the output is. It seems that the pick up response is directly proportional to the vibrating mass of the string. Your pu do not suffer this illness. Do You have a tentative explanation for that? The custom pick up is Music Man alike, with Anico V poles of 10mm diameter and is a triple bucker, that is it features 3 rows of poles. (maybe too strong magnetic field?..) Thank You Sheldon. By the way, rain and sunnyu here in Milan, Italy: from 30 degrees down to 18 degrees 3 times a week. Your neck stays still like a Greek Temple. It seems that You have found really the good recepy for stability, really. BRAVO!!!!!