So after returning for my first half-strength feeding after flushing several times, I think I found the culprit --- the syringe I was using to measure out the nutes. I thought I was measuring cc's, or mL... It was in tsp! So the first feeding which should have been half strength and the two feelings after that were actually like 2x strength. FML... So I believe what happened is I caused a nute lockup and created a cal/mag def after the initial nute burn. On the brighter side, the tops have recovered and I see trichomes forming again. Lower half has permanent damage but hopefully I can get at least a little yield from the girls. Better late than never, live and learn right? Thx for all the help!