Get some deli cups (16 oz) with vented lids with the black grid stapled to the bottom. Put either silk chow or horn chow in the bottom of the cup ontop of the staple holding the grid to the cup. put the eggs on the upside down lid and turn the cup upside down ontop of the lid. Leave it that way until they hatch and climb the grid to get to the food.
I have never had any issues with a little moisture and hornworms. Silkworms yes. Silks die if you look at them funny but I had zero dieoff my last batch of horns and I must have hatched out 500 hornworms to feed off and gave away 2000 eggs. The deli cup method I describe works like a charm. JMO