Spitz,
Use what you got. Sounds ok. It is fast draining so you must watch that you don't kill your seedlings by drying them out. One mishap means to start all over again. Bottom heat, hi humidity, soil just a little damp. And for weeks. One oops, all over. I use a covered container. Like the take out dishes with the plastic top and black bottom base. Makes a nice tiny greenhouse.
Some start their seeds in a plastic bag moist. When they see the seed germinate, they plant up in a pot with a plastic bag over it.
I use a cactus mix for seed starting then transplant in a month or so into a more gritty mix.
Every one and every where is different. Experiment and report back to us to show us more.
Stush