Fall Creek Tuning!
I wanted to report that I just had some Yamaha bars retuned by Bill Youhass at Fall Creek Marimba, and I am very pleased! i think Bob Leatherbarrow had posted about this, so thanks for the tip Bob.
I sent my 442 bars, and had them retuned to 440 (so I no longer own 442 bars - yes, finally... they make no sense in the US). Comparing Bob's 440 tuning with my other factory-tuned 440 Yamaha bars, they are much smoother. Much more in tune with themselves, with less peculiar artifacts.
I highly recommend Bill's tuning skills!