Here are some pics:



I have the "+10" gray extension collar open on the Deuter, about 1 roll on the roll-top of the Circuit, and 1 L water bottles in both side pockets of each pack. As I said earlier, the main bag of the Circuit isn't huge but you can fit a lot of stuff in its large external pockets.
FWIW, ULA has a very easy return policy. I originally ordered an Ohm 2.0 but decided it was too small. ULA e-mailed me a pre-paid shipping label and had my Circuit sent off before I even put the Ohm 2.0 back in the mail.