How does the medium duffle handle when it's not fully loaded? Does it somewhat keep its shape? I have a 257 that I use as a work/day bag but I need something for the weekend. I've been looking at both the medium duffle and the large travel bag. They both have the same height/depth measurements but the duffle is 25" long whereas the travel bag is only 20" long. I'd like the versatility of the longer duffle (could be used for week long trips) but I'm afraid it's too big for just weekend use.