Steve Nosko wrote:
(snip)
Don't (some) zeners generate noise???...or is that only near the breakdown
reigion?

I think that whether noisy or not, the noise generation mechanism
kicks in, only when the zeners are reverse conducting via the zener
breakdown process, so if you keep the voltage well below the zener
knee, say, half of that, they are not particularly noisy compared to
other diodes. So, yes, only near the breakdown region, especially
just below the rated voltage (low reverse current).