How Low Can You Go?
I use Dean Markley Blue Steel strings, gauges .010 - .046, and I use a .059 gauge string for the low Gb (I've used a .056 gauge succesfully, too.) As far as tweaking, what can I say? The ONLY (slight) buzz I had was on the lowest string, frets 1-5 or so, and only discernable on the acoustic output of the 2027. I adjusted the truss rod MINIMALLY, and buh-bye. The buzz was gone. As far as action, my action is pretty darn low! Serious. I don't like high action (Slightly higher on the bass side, and lower on the treble strings, but overall, low.) And no buzz (Optimal word is NO buzz BTW.) I guess Ibanez just makes a good guitar... but then again, I have a Squier 7 strung identically, and the action is only a tad higher.
The only problem with this tuning I've found is that since the Gb is so low, the 25.5 scale isn't long enough to accomodate the proper intonation. Everything up to the 12th - 15th fret or so is ok, but it gets a little skewy after that. But, this is ONLY on the low Gb, and I never play notes up there on the lowest string anyway. Everything else intonates just fine, and the trem is at the correct angle, plays smoothly, etc. I plan on checking out a baritone scale neck (27") in the future to see how this affects intonation on the low string.
I've said before in other posts, I do play low, heavy riffs with my guitar. I'm an unashamed KoRn, nu-metal fan. But, the nifty thing is these real cool two finger major/minor baritone triads you can get with this tuning. And you can have full 7 string chords that just ring out... very piano-like.