Ok so the cal-mag thing isn't super far-fetched because it is low Nitrogen, so starting plants out low is always best, as far as the forcing water usage I can't say. Cal-mag isn't otherwise a necessity, "unless you need it" which is more likely in soilless and less likely in soil.
Starting seeds or transplanting or whatever right when the lights turn on, is best if it's best for your schedule. I don't think that matters much. Honestly though I like where your head's at with this and I hope you figure something out we haven't learned yet.