I would imagine that raw oats are going to be lower glycemic than cooked oats regardless of how small the particles are. And I doubt putting them in a blender and then cooking them would do you any good either. When they are cooked, they are basicly turned to mush. My guess is that mush would have the same glycemic effect regardless of whether it came from large peices or small pieces. Quick oats are higher glycemic than old fashioned oats, (65 vs 52 or something like that) not because of the smaller particles but because the milling proccess removes some of the fiber allowing for quicker digestion.