Boot Fit

Boot fit is a process. My personal story is that I went from a 28.5mp boot last year to a 27mp boot this year. When I first put it on I was wondering whether I would ever feel good in the smaller size. After working with the boot for a while I wasn't sure if I couldn't go down another size comfortably.
I had been sloshing around so comfortably in my old boots, I'd forgotten how much more solid I feel in a performance oriented fit. I like to describe it by referring to the 'bell curve' noting that under the bell are the great days when the boot feels perfect and under the end of the curve are the days you've crushed the liners out to ultimately an unbareable size. Under the first part of the bell are the days when the boot feels brutally tight. You have to go through them to get to the good days. If the boot starts off feeling great you have nowhere to go with it. It will pack out and you'll be bumming.
There are reasons you can get into such a smaller size than you think you can at first and not the least of them is that you ought not be buying boots in July north of the equator at sea level. If you do nothing other to the boot than buy it you'd be foolish not to spend the $35 or so for a pair of decent drop-in footbeds or better. In most cases these footbeds will provide greater arch support than the factory versions. The slight lifting and support of the arch shortens the overall length of your foot in the boot hence the second reason for a smaller boot.
Often skiers too soon reject the feel of a boot on their foot purely on the basis of a 'hot-spot' of pressure upon its first wearing. Forget not that most liners of quality ski boots made today have a moldability usually through a heating process to mold the boot not only to your foot on the inside but also to the boot shell on the outside of the liner. Aftermarket liners of higher quality are also available from makers like Zipfit. The custom molding often eliminates hot-spots and uneven pressure spots.
I went with a custom moldable cork footbed from DownUnder and even with my considerable experience, it took a couple of grindings to get them even. The key was being able to discern what isssue was the footbed and which was my turn. It took some experimentation but I finally was able to work out how to grind the footbeds to even out my turns.
Boot fit is a process. The key to it is your ability to communicate to your boot fitter just what is gonig on in the shell. It takes skiing it a couple of days and going back for adjustments. That's another reason to buy the boots near the hill. Don't worry about sounding like a pain to the salesman. He's expecting you to come back and wants you to give him feedback so he can help you get it right. There is no reason your boots shouldn't be warm and comfy with great performance once they are broken in.