I would personally get some egg crate/light diffuser. Putting them on the substrate is such a headache and if it's too moist or too dry your babies will die. Putting them on the light diffuser is stress free and super easy. I honestly don't know why people don't do it. You can totally soak the substrate and not worry about the eggs for a week+ at a time. You don't have to measure your humidity, nothing. I haven't measured the humidity in my egg tubs for 3 years now. I also don't use press-n-seal, just a $1 shoebox tub, perlite, and light diffuser.