I wore medium length night dress from the start as it was easier to lift up when dilating. I used to wear jams but now I wear the nightdresses that I bought for the hospital unfortunately now they just come off before I go to sleep, hehe. So I guess as long as you are not loosing then you can wear anything you want. I was pretty much healed up after seven weeks so I wore nothing but my nightdress since then (well, as I said until I want to go to sleep). I have always slept like this a bit like Jenny I guess.
Getting air to the healing area, well just helps the healing process as if its moist then it will take longer.
Stardust