Well peeps, I just loaded up the Photone app, made a diffuser from the one on an LED bulb, and checked the light level on my droopy girls.
If the full spectrum led selection works for my DIY mix (it should, it includes both daylight and soft bulbs, so covers the entire spectrum, perhaps absent deep reds), the girls were receiving far more light than I expected. I will do some more checking, but at this point I am quite suspicious of my par meter.
Thanks to the earlier comment by
@Fermented_Fruitz on excess light causing droopiness. I would not have checked this with the Photone app otherwise. More later about this.