I use the substrateless method too, and I have plenty of condensation. I don't think that press-n-seal or seran wrap is needed with this method because the perlite is so wet that you don't have to worry about some of the water evaporating. With verm or hatchrite, the media is dry enough to start with, so you don't want to lose any of the moisture. I just make sure to not have any of the eggs touching the sides of the egg box so they don't come in contact with the condensation or water drops. I get some condensation on the lids, too, but it hasn't been an issue with the 3 clutches I've had so far. I was worried about it dripping on the eggs, but it hasn't affected anything. I am planning to get a few of those super absorbant shimmies and cutting them to fit the inside of the lids, then hot gluing them into place to absorb any condensation above the eggs, but it probably isn't neccesary, from my very limited experience.

If you're worried, another option is to make some sort of a concave (or would it be a concove?), that's glued to the lid so any condensation above the eggs runs down and away from the eggs. Something like a 10" cylinder cut longways to fit the inside lid would work so any condensation would run down and drip off along the long sides of the egg box. I know mushrooms are sensative to water drips like eggs, so some people who grow them use a kind of cone shaped glass lid to get the same effect.