Sorry of sudden question (and hope it's right place):
Though I start interest in voltnutting pretty recently (maybe approx a year) I see a lot of zener's buffer here, in datasheets (like on 1st img) and in DVM's schematics, and almost in all cases zener startup is like on 1st img, but why not use jfet startup, like in img2? It provide reliable startup and almost no current after, so high PSRR. I see no drawbacks in this setup, but as almost no one incl big companies use it, seems I miss something? Well, I could guess a HF noize feedthru via parasistic capacitance, but resistor behaves same, and this could be reduced with bead.
PS: I ended assembling alpha version of pure DAC reference scaler, it's intended to use w/lm399, but as it's hard to buy it for me now, I use jfet (as in JVR thread). It's ok to post here, or create dedicated thread?