@Zenman, Thanks for the welcome. Sorry I missed your question. ("I am a zinnia hobbyist. Just out of curiosity, what kind(s) of zinnias did you start this year?"). I started Big Tetra Mix, Cactus flowered mix, Cut and Come Again, Benary's Giant: wine, yellow, white, Benary's Giant Mix, Zowie yellow flame.
Usually I just take the hoe and lightly make a fairly wide row, abt 4-5 " and abt 1/2 " deep, drop my seeds, and then cover with garden soil sifted through a small screen I built, then tamp it down with hand or back of hoe. Water almost every day.