Cant speak for Kitzbuhl but if you go to a ski shop not right next to the lifts, they will be less busy, usually cheaper, explain your problems and that you intend to buy a pair of boots. Some will find a very new season hire boots for you to try. Test it for the day, then take it back, if its no good change it, if its snug and pain free, then some will give you 2 choices, buy a new ident pair less the days hire cost, or if they are like gloves ive known mates buy the newish hire pair at a a reduced rate.
I have similar problems but to just one foot and have new boots stretched, wide fit, moulded inners, you name it. Usually fine for 3 hours then the agony starts, cramping pain which almost feels like the circulations gone, but no signs of rubbing, pressure etc. I am as we speak seeking further help in my efforts to conqueer the problem. Ive had someone with a knowledge of sports medicine suggest that with a ski boot and the angle of the leg and weight distribution that it puts all the weight on the balls of my two smallest toes on my right foot which in retaliation after a while cuts off the blood supply to part of the foot hence the discomfort. If thats whats causing it then how the hell I cure it I dont know!! Like u I have to remove the boot a couple of times a day. When all else fails drink heavily!! :D
Been 25 years since I was at Kitzbuhel, but we stayed just outside at
Aurach I think it was called. Quieter but ski shops and ski school staff were very helpfull. Good luck in your quest, I will monitor this thread in case anyone has pearls of wisdom for you which may cure me!!!