What about C2-G2-D3-A3-E4-C4?
- First string is lower in pitch than the second; which could theoretically get confusing.
- Without a fourth interval between the second and first strings, you do lose that beautiful ascending V-I option (especially with harmonics).
- Low C may be optimistic with nylon strings (but is fine for steel).
- All the fifths relationships of the Guitar Craft tuning (C2-G2-D3-A3-E4-G4). Two complete four-string groups in fifths, allowing lots of fifths-based scale thinking and chord construction with no need to "skip strings".
- For fingerstyle, a minor triad on the top three strings. With this voicing, at least some common alterations may present very convenient left-hand fingerings.
- First and sixth strings are two octaves apart. Lots of people playing standard tuning and DADGAD take advantage of this.
- The first string becomes a simple pivot between CGDAEC (root position Am triad on top 3 strings) and CGDAEB (GAD intervals on top 3 strings). Or, for that matter, CGDAEC# (A major triad) or even CGDAED (which is theoretically another GAD variation). Total retuning movement for the first string here is a minor third--very do-able--and well within the range of appropriately-gauged strings. And, the GAD variations re-capture the ascending V-I arrangement.
- The possibles of using these intervals with partial capoing seem immense, almost intimidating--and yet above whatever capo(s) are placed, I've still and always got five strings in fifths to work with.
I will have to try this out. Since I don't have years of fingerstyle under my belt yet, it may be that I can adapt to this easily enough to take advantage of the benefits. The more I think about it, the more interesting it seems: the first string is the only thing that ever "moves", and yet it seems like there are four very individual tunings there.