Bedouin
I had the fleetside slant saddlebags
Link. I have looked at the dimensions of both and there doesnt seem to be much in it. Maybe it is the angle of the slant, or maybe that the W&M are soft bags, but I seemed to be able to get more in the W&M than I can in the saddlemen. If I could turn back time (queue Cher song!) then I would probably go with the W&M in preference to the Saddlemen.
re the brackets, I just found some cheap brackets in a bike shop. Turns out they were not long enough and in the end I "customised" them with some BBQ forks (with welding done by a friend of Dinqua!) Didnt look nice at all but I never had the bags off the bike so didnt matter. Sorry that this doesnt help you!
Nobby
