If strings are going sharp as you move up the fretboard, then either the guitar is poorly intonated or you are pressing too hard when fretting them. 'Sweetened' tunings are not designed to correct this, and nor can they.

From the OP's description it sounds as though James Taylor's version of a sweetened tuning is in effect a stretch tuning, where each octave interval is set to be slightly larger than the theoretical doubling of the frequency. This is routine in piano tuning so that might well account for why a guitar tuned this way sits better against a keyboard.