Hey Don,
I think I can appreciate about the ´more air´ concept. As I have been experimenting with 2 types of compost. One with more bits while the other is more the typical dark coloured compost. It appears that most of my seeds in the compost with more bits germinated and grew quicker.
I noticed in one of Charles´ updates that he also sieved one of the compost and the other not sieved and the seeds and seedlings grew better in the not sieved compost.