I love my various bits of wolfman luggage. For my 640 I've already purchased a set of ortieb dry saddle bags, and am just looking for a way of keeping them off the side panels and exhaust. At the moment my setup will be Ortlieb saddlebags, Wolfman Enduro Tank Bag, and Wolfman beta bag. Should be plenty for a longish trip. I like the beta bag, but on it's own it's just not enough for camping off the bike. I think the saddlebags will let me get away with leaving the duffel behind.