When I get a sleeve for my Macbooks, I like them snug. The only sleeves I can find on ebay are for unibody, non retina MBs. If I were to buy a 15" non retina sleeve, would my 15" retina have a lot of extra space to slide around (which I don't want)? Just by looking at the photos of non retina and retina size comparisons, it looks like it will be too loose. Does anyone actually have any experience using older model sleeves on their retinas? Thanks.