Sony Diaries #1024: portable lighting setup for group portraits

I was getting tired of lugging around what looks like a body bag: a case of 2x 500W/S Elinchromes, stands, umbrellas, mounting rings, and extension cords to places that may not wall sockets. I could use battery-powered monolights but the volume of group portraits that I do doesn't justify their purchase. Recently, I was commissioned to shoot a group of 40+ at the Royal Ontario Museum.
Since I already have 2 Godox speedlights, I decided to add a third one (as backup), and a Godox X1T radio transmitter. Shown in photos is my setup (taken with my LG G5 cellphone.

 Sony A7III, Godox X1T Transmitter, Tamron 28-75F2.8

 Godox TT685 Speedlight with a Gary Fong Diffuser

  Godox TT685 Speedlight with a Gary Fong Diffuser

looking at the Speedlights from POV of the subjects

1/40 F5.0 ISO2500