Tom, I have had a thought. I have a Strat that, if tuned to a tuner, never quite sounds right ( it is an old Strat btw) and over the years I have got used to tuning it by tuner and almost subconciously tweaking the tuners as I know what it needs ( I have had the guitar donkey's years). It could do with a set up and fret dress but I have never got around to it. In my current band we tune down to Eb and I found that it behaved a bit differently and I put that down to less overall tension on the neck and , as before, I can almost tweak it without thinking. What I am saying is that perhaps if you try the open D and tune it so it sounds in tune you might find that it is Ok.