You can do either. I use the regular lids, unless the clutch is large and would touch the lid, then I use press and seal. If it is a really big clutch, I use a 12 qt tub rather than a 6qt. If you use the lids, just check on them every once in a while and wipe the condensation off the bottom of the lid. Water dripping off the lid can ruin an egg.
The best thing about your method of incubation is that you can add water by pouring it in the corner (be careful not to get the eggs wet) of the egg box.