I worry about using off-pitch alternative fingerings at all. (I just posted about this in uk.music.folk, apropos the poor intonation of keyless flutes in inexpert hands playing Irish session tunes). It might seem like that flat C sharp doesn't matter since it's over quickly, but how many of those C sharps are there? In this example it has the effect of implying an A major chord, and people *do* notice if chord tones are out of tune, even more so if there are lots of them. Maybe the flattening might put you near a mean-tone third, and if the people you're playing with are in mean-tone too that's just peachy. But usually, not.

This isn't such a hard tune in the standard fingerings if you work at it a bit.