A couple of questions for those who actually have this product:

-Is there a fabric shroud with drawstring closure on the main compartment or is the opening narrower than the flap is wide?
-Just how big are these bags? The size on REI's site is stated to be 1,465 cubic inches, but the math on the product dimensions listed works out to 1984.32 cubic inches...

Also, would you be willing to measure the length of your chain stays and rack platforms? I ask because I had heel strike with my last saddlebag panniers caused by the 16.3" stays and 12" rack (with 26" x 1.5" tires). The way that these Timbuk2s mount at an angle may allow me to go back to panniers.