Wow, what a difference one week makes!
That one plant with the quarter inch rootling? Three days later it was downright bushy on the bottom! I set up a second bucket exactly the same as the first but with the “grow” nutrient mix instead of water, and (after spending half an hour learning valuable lessons about pH down and pH up and the importance of getting it right the first time and not overcompensating multiple times and then having to start over from scratch) I transferred my first rooted clone into the bucket.
I’ve transferred a plant a day since then too! I guess I’m doing something right!!!