My first year, I used Hatchrite, no diffuser - though I bought a panel of it. It still sits in a corner un-used.

Every year after, I use straight Perlite, water added to be just barely moist to the touch.

I use Sterilite 7 quart locking tub, no ventilation holes. I've used Press & Seal previous years, but didn't this year, I didn't notice much difference. I open the tubs when I think about looking in on them, but I mostly ignore them until about 2 weeks before hatch date. I'll peek in about once every two weeks, and if I notice pre-mature dimpling of the eggs, I'll add about a TBS of water to each corner of the tub.

I have incubated at 89 degrees in past years but chose to incubate at 87 this year. I've had noticeably bigger babies by incubating a few degrees cooler and letting them bake a little slower.