|Arkel bags are great for touring|
The rear panniers are Arkel GT-54 models. The first thing you notice about them is the left and right panniers are not identical. The right pannier has a long tube at the rear. This is for long items like tent poles or Thermarest pads. It's detachable, so you can remove it if you don't need it. There are plenty of pockets on these. I always used the lower outer pocket on the left rear pannier for my lock, keys and wallet. That way I can quickly lock the bike and get my wallet whenever I stopped somewhere.
If you have bulky items that don't fit into the panniers, you can use bungee cords to secure them to the top if the rear rack.