I think people fuck around to much when it comes to seedlings or clones 99 percent of the time its human error Keep it simple method , which includes time i suggest anyone reading up on natures clock as in seasonal planting and sowing to grasp the concept...
I mean not sure what is taught in schools anymore but this is elementary
i seed in feb out door in green houses with no ill effects even indoor my rooms are in low 50's Cellar area ..
One of the first things any grower should invest in is a a dome and tray and couple T5's and thermometer.. run dome or couple days fine tune it so temps are in the 70's and your on your way
If your new to it all run trials before starting expensive seeds go purchase some seeds like tomato's peas anything etc just to get hang of it place towels under dome to raise it from cold tops etc ,, its really that easy if temps cannot reach 70's then cover dome with towel etc
5 -6 years ago i used to seed approx 450,000 seeds for spring run starting in end of Jan ( Botanic garden ) let alone clone from them all for yearly sales once you realize or get your sequence , and all aspects in order its simple
anyways good luck find your way and run with it