Originally Posted by azza_333

This doesn't answer you question but I hope it helps. You will always be at an aero disadvantage with panniers front or rear, handle bar bags, and even seat post bags. You seem to be after light and aero for touring, my solution to the same problem is ditch the racks and panniers altogether, and go with a top tube bag, frame bag, and a seat bag, that set up will get you as aero and light as possible whilst bike touring, and will allow you to carry 20L of gear, that should be more that enough space to carry everything you need, myself I take 12L of gear on long 2 month tours including tent and sleeping bag.