Robin, thanks for getting back to me.
Output on high was about half that of high with a full 123, and MUCH higher than low with a full battery.
Rough figures I got with an aging DMM:
SF 18350, 4.17 volts: High 3.4 Amps, Low 70mA
New 123, 3.27 volts: High 1.9 Amps, Low 100mA
Depleted 123...