Didn't mean to dismiss the value of obsessive practice/rejigging/adjustment (I suppose this could be considered a form of analysis) in my earlier post- this is of course an integral part of doing justice to a song, making it work with one's own vocal cords/instrumental style etc. Just that I personally would give primacy to how it SOUNDS (and yes, one's intuition is probably the best guide here IMO) rather than when/where the song originally came into being, what chord groups/tunings/instumentation would've been available to the original composer, blah, blah. A song, and its performance, ultimately stands or falls according to whether it sounds good to the people who comprise its current audience. I doubt whether many would disagree??