Mark, I think the lights during winter, if you will continue with it, will help keep the cuttings warm, but cannot expect a bloom or leafing on unrooted cuttings for the time being. Even in my area it takes late May to late June to see anything going on my Plumies. But then again, even if it may be warm to hot here already but our conditions goes very dry, so maybe the very low humidity we have hinders its wake up time, compared to areas like Florida that have better humidity levels. Plus there are varieties that really takes it sweet time to leaf.
And I think that is why rooting cuttings is best done around Spring time, where over all ambient conditions is getting warmer longer with the longer light duration. In late Fall to winter, getting cold and less light, and this plant really loves lots of sun and light, so it is just not enough. Best to let it naturally go to sleep. As I have suggested before, experiment with one or two with that artificial lighting and let the others naturally rest, so you have back-up. On the flipside of things, less things to do really in winter, for me I like that, it will just slumber along together with its friend Adenium.
Your cuttings may have latent buds, so it may wake up ahead in Spring.
Something to look forward to later.
