Another thing about off the rack footbeds. Don't take the MFG's word for the correct size. Consider that they are "cut to fit". So, go to a shop, take off your shoes, leave your socks on if you wish, sit somewhere where you can dangle your feet, and have someone (sales person or buddy) slip the footbed onto the bottom of your feet so that the arch seems to be right for your foot. Then look at the heel cup and see if that cups your foot well or if there are gaps. Don't try to make it fit your foot, Find the one that is most shaped like your foot while dangling. (closest to neutral without someone setting your foot) Then put the footbed on the ground and stand on it and see how it feels. Any pressure points that really feel like they are in the wrong place? If the arch feels like it's pushing on your forefoot, then you probably need a size smaller. If it feels like it's pushing on the heel edge of the arch, you probably need a larger size. Once you have found the footbed that fits your foot, then take the stock el-cheapo footbed out of your skiboot and use it as a template to trim off the front edge of the footbed with a pair of scissors. Start by cutting them a little bigger than your stock footbeds and then slowly trim to fit.
For example I ski on Instaprint customs, but for my street shoes I use Superfeet Cut to fit's. I have a 9" foot (according to the shoe measuring device) using the size listed by Superfeet that would put me in a "D" footbed.
This footbed has the arch too far back so I buy the "E" and they fit perfectly. You just have to trim more off the front.