If you all have time for one last question....
Here's what I came up with. "Transmit a signal when the sun is shining."
RF transmitter (indicated by Rload) runs at 3V, 22 mA, shuts off at 2.7V.
6V = two 3V solar cells in series.
1K chosen to shut off the RF transmitter load when it's cloudy.
The zener is 1/4-watt (not 25-watt).
Your examples showed a circuit like this could tolerate a transistor, so I used one.
I've quit worrying about extra current from the solar cells, it's a myth.
Will this work?
Thanks for your help.