I'm going to but on a Micatech top case but would like to know how much weight can I put in a case mounted with your rear mount setup? This is for an R1200GS. I'll not be using it to store my helmet or jacket in while I go into Starbucks, doesn't look as cool as bumping into everything and one while knocking stuff over I'm leaning toward the big case but if weight is the issue I will be satisfied with the medium. The front mount makes it easy but I'm trying to figure out how much is to much to load not going overboard with the rear rack but understanding my maximum capacity. I also want to use the roof racks on my Pilots which is another reason I want to use the rear mount.