Beginner needs help with first time clay mold casting
I'm brand new to sculpting and I got Silo 2 water based natural clay to practice with, with intent to recycle it. The first sculpture I made is on a Styrofoam wig stand and goes up to the ear line, so it's not a full head. I'm quite proud of how it came out and I'm a bit emotionally attached and I wanted to make a silicone mold of it to create a permanent version of it, so I could keep using the clay, as well as experiment with mold making.
Problem is I found so much conflicting and 10+ old information online and I'm hoping for help getting all the information straight to get the best results possible.
I've read that silicone molds won't dry on clay that has sulfur, but I haven't been able to find if my clay has sulfur in it, it's not mentioned on the package or the silo 2 website. (when I get better with sculpting and want to make a mold, I'll buy proper clay, but I wanted a cheap clay to start with) I've also read that if there's doubt on the sulfur, I can spray the clay with some kind of sealant spray, but I haven't been able to find if these kinds of sprays will make the clay non-recyclable, same with easy-release sprays.
I would also love advice on what to cast in the mold for a high detail paintable result.
Any advice is much appreciated.