Been doing a big more digging around for info to help me choose a rack and luggage, now I'm aware that heel clearance might be an issue. My bike's chainstay is 435mm long and I've seen suggestions that the bare minimum chainstay length for avoiding heel-strike is 440mm - only 5mm difference but I have large feet (euro size 48 or UK size 12+) so heel-clearance will be more of an issue. Some racks, like the Tubus Logo, allow you to mount panniers further back on the bike and I was wondwering if ther Topeak Super Tourist DX that I'm keen on also allows that?