i also use the "over water "method but a little different than most.
i use the blue cliplock "sistema" tubs and put either 10mm-20mm water or a very sloppy mix of water and vermiculite.
i then put about 10 mm of dry vermiculite in a plastic 18 compartment storage container bought from bunnings.this stops any mould travelling to other eggs,stops eggs from rolling and the dry vermiculite soaks up any condensation droplets.
i then sit the eggs in the compartments then place it in the sistema tub and into the incubater. i also crack the lids once a week.
i have used this setup the last few years and had near on 100% success.last season i only lost lost 2 eggs out of 96 but that wasn't due to the incubation process.
cheers
simon