I have a feeling that a small string of Schottky would be a cool idea. Forward biased at ~.4V each. We'd need more than two, but it would offer a far finer adjustment of the bias voltage.I suspect that the Schotky would be quieterin fwd bias than a Si one would be. Nice suggestion I must say. If I didn't need a 20-30 of them in the new one ( instead of 6 red LED's ), I'e be solderig up a string.
regards,
Douglas