I don't use seed starting mix. I never saw the need for it. Just a bag of potting soil and a bag of perlite means more nutrients, water retention and strength.
I mix it in a container that is 3-4 times the size of the mix.
I have tried just the flats filled with dirt, but separating the plants is difficult and annoying. The Jiffy 6x12 cells work well.
As soon as the plants germinate, I drop the lights down to about an inch above the plants. Just plain old shop lights on a timer to run about 18 hours a day.