Try Newtone strings, but not the lightest. Both my Martins stay in tune and sound excellent. Yes the Tacho is quicker to capo (the Martins have to be retuned very slightly for every capo shift - but most guitars do) but up and down the neck (I play up to the top-but-one-fret) with just fingers and they're bang on, all six strings, in any tuning.

Newtones are completely different to any other string type, and a godsend to any guitarist.