Yes, I sympathise as I have the same sort of problems. I got a pair of Altberg at 11W and they're a bit too short, so I'd probably need a 12. However, as I said before, now that I've cut out the dratted toe guard on a pair of Meindl suede, goretex lined boots, that I really like but couldn't wear for long, they're really comfortable and they are 10 and a half!...bit draughty on the right toe area though! Again, got a pair of cheap Karrimor size 12 and they're just right in the width and I pulled the toe guard out of them and glued over the seam. They're doing fine so far.
As boots are generally so expensive, or most people would want to wear them for long days out walking, it's probably best, whatever sort of slight imperfections/difference in sizes your feet may have, is get good advice from specialist shoe shops that supply or can provide a wide range of boots to suit.
