I haven't been able to follow up on this - most of the fixes are best in summer weather anyway...
A curious thing though... we had a freezing rain, sleet, snow event late last week. Temp's were at record highs ~50 degF Friday, and then back to -10F last night. The blades, tower, mount all had a thin frozen layer of ice, but I started the turbine on Saturday morning. It had been lulling about, so there didn't seem to be any imbalance. The output was a bit diminished I'd say, but the blade whistle was totally gone! And, the plate vibration was also negligible.
On Sunday I scampered up to look it over. The plate and tube were sort of welded together with a seal of ice. The blades had a smooth, but irregular coating. There was virtually none on the leading edge, heavier near the thickest cord section; spottier on the trailing edge. (Should've had my camera).