Hmm. This needs some pondering - ! My Super C rackbag can be whipped off in seconds using the Velcro straps. However the issues of adopting a saddlebag for an average of three days a week. would be as follows -
Using the saddlebag clamp would mean fiddling with the straps on a regular basis and the ensuing wear & tear on same.
Also, as there is about 30cm. vertical clearance between my saddle and the rack, there would be a lot of swing from the unsupported bag.
Using a Bagman support would - as far as I can tell - interfere
with the rack when I wished to use the rackbag; one or the other, not easily interchangeable.
However, having pondered the splendid Carradice website in more detail, I think that the Super C SQR Tour may be just the ticket.
Just have to do the spatial arithmetic to ensure that I can crowbar in my lunchbox, those necessary 'basic' tools & spare inner tube, uniform shirt, keys, wallet, smartphone, oh, and wet weather 'extras' that are required for this time of year - !
Thanks for the input folks - !