I've always buried them, the bottom ones don't need for me to be able to see them to hatch. I use moss underneath and not vermiculite, but usually when I lift the pad of moss on top to check them there's a few at the bottom I can't see. I like to use enough moss so I can't see any eggs without lifting it, if it starts to dry out I can spritz the top pad of moss without spraying water directly on any eggs.
The way I feel, if an egg on the very bottom is going bad, if I try to mess with it the chances of damaging all the good eggs around it are pretty good.
I'm glad they are plumping up