I also have a big head - my system is this. I only use 5 small pads (cut up foam knee pads) - 2 on my forehead, 2 in the rear (just behind my ears), and 1 at the back of my head. Helmet sits snug and doesn't move and has never shifted or fallen off. I only use a very thin (maybe 1/4 inch thick) foam pad for the top of my head, so basically the top of the helmet is resting on my head.