Well, I've fitted the RackTime Addit to my bike, clipped on an Ortlieb Vario to see how well it fitted, and was disappointed. Whilst I can fit the bag further back on the rack to minimize heel-strike, I couldn't secure the lower part of the bag because the elasticated hook (not a bungee, just a rubber strap) can't be positioned at an angle to hook on to the rack. I tried a number of adjustments of the mounting system but to no avail, so the Vario is going back to the shop. I've also ordered an Arkel Bug so I'll see how that goes, hoping it'll work better than the Vario so I'll be able to use it on my daily commute.