When doing substrate less method do NOT use Press n Seal. This will cause extreme condensation on the lid and sides after only a weeks time. Which is turn causes the eggs to sweat and die.
Also when soaking vermiculite, be sure to have a way to support the light diffuser orther swise it will sink it over time, and bottom of eggs will get wet. In turn causing mold to grow and possible killing the egg. I just double up on the light diffuser so if one sinks other wont.
Works like a charm and i dont add water ever during incubation.