Actually aerial film is either 9.5" wide or 5" wide. I don't think I've ever seen 8" aerial. (I'd be happy to be proven wrong). One thing about buying 10" and cutting it down. They don't tend to cut film to special sizes if no one buys it, so the more people to buy, even if to cut it down, the more likely they might still make cuts in those special sizes, so go for it. (I still think it would be easier to get precut)

Jamie