Transistor CCS resistor value calculation.

[valves4amps]

Hi Jeffrey, the point of this cascade circuit is that the lower transistor with high gain may not tolerate the higher voltages that may exist across the whole network. So the upper transistor is closely controlled by the higher gain lower one.  Also the temperature coefficient of Zeners ranging from + to - is around zero at 5v. I agree totally with your summation of resistor values.

Dave