Very neatly executed!

Thank you.

I assume the vertical boards are the Ag102 and the horizontal ones are
your I/O circuits. Is that right? What did you need to add?

Correct. XLR rack mount panel is from Jaycar. I chose to use a microcontroller to detect and signal float conditions: one 8pin ATiny13 and its associated 5V supply and voltage sensing parts does a pair of charger channels. I resisted the temptation to indicate bulk and absorption charging state by flashing the LED at different rates (except as an experiment during development).

The Shortform doc says the charger IS temperature-compensated but also
says that "With the addition of a low-cost thermistor, charge voltages
CAN be temperature compensated". Which is right? Did you have to add a
thermistor yourself?

Yes, you do need to add the NTC: one per channel. I chose not to temp comp because of the perceived challenge of measuring the (correct) battery temperature in a club situation. But I left provision on my pcb to provide temp comp.

Is there an NZ/Oz distributor for Silvertel?

Fairmont Marketing. www.semiconductorstore.com also ship down here.

Cheers
Neil