OK, here goes.
Using a Fluke 335 True RMS Clamp Meter.
Power on,
Top thermostat lead, (black and red wires), tested at 241 volts.
Power on, top element, testing ohms, 13, solid beep.
Power on, lower element, ohms, 0.0, beeping. (One of the elements was on, shower was running, if that...