Tourist in MSN : I've seen your pannier setup before in your other posts. I love my Jandd trunk bag (big expandable one, ex-police found at goodwill), but that rear racktop bag sure does make sense instead of that, if the panniers are high enough to stabilize it. I like the panniers on the lower rack tier, but they should be that high when full. I'll just have a rigger's bag or something similar with tons of compartments, for all my tools and spares inside the racktop bag.
At one time, Ortliebs seemed expensive to me (my other panniers are ancient Nashbar, and used REIs that were returned and cheap), and copies are priced at half, but the actual cost delta isn't that much, worth it for a tour. I'll just wait until needed, and put the townie wear on my old ones.