Erm, use harmonics. You get more high content and the harmonics are going to be perfectly in tune by the basic laws of physics. That's how I get my basses and the 7 tuned with guitar tuners. If your tuner likes highs, give it some fucking highs.
Jeff
Come on now, I don't use anything but harmonics to tune but I suppose the post was misleading. I'm saying that my X3 does not like the 12 fret harmonics on the low string of my guitar and especially my bass. If I tune with the POD, chords are very out of tune. If I use any other tuner, everything is in tune.