With either the stock saddle or a Brooks the loops on the saddle will allow for almost any bag to be used. Or , if you have a bag you like, sew two paracord loops on the top at the same width as the saddle loops. Pass them through the loops and use a bit of bamboo, a dowel or any straight stick to go through the loops and secure the bag. I like having a saddle bag big enough for a bottle, a sweater and maybe a tool roll, say foot long and 8 inches wide and deep. It's fairly aero and since it only is used for light things doesn't affect the handling of the bike. Velo Orange sells some nice creatively inexpensive ones, including a Minnehaha bag that will hold quite a bit. Don't know about your shipping and import costs, though.