Trawling around in different directions (as usual) I picked up a proper lighting stand (Portaflash lighting stand 3S, from Tecno) to make a portable backdrop. I need a portable setup for some upcoming headshots for a local hairdresser friend. Also picked up an umbrella (AVI RV40 40" from eBay). They were amazingly cheap.
I drilled a hole the center of a copper T-joint (plumbing supplies) so it would fit into the top of the stand, and drilled two holes in the ends of the joint to take a pair of rings. I ran a 1.5 meter length of 17mm dowel rod through the two rings, and hung the cloth over that, with clips. Balanced, simple.
With the backdrop 1.5 meters wide, I could stand 11ft away and still keep the whole sheet in frame (focal length: 65mm). That allowed me to put the model as much as 6ft from the backdrop and 5ft from me if I needed to.

One flash on the umbrella, another straight up with the catchlight card (both wireless) and sometimes a third (with or without snoot) on a tripod (optical sensor) facing up at the backdrop.

Every tweak of the lighting brings up different results ...
