Wow, I'd never thought of altitude! Normal differences in humidity is just a little more or less water, that's why method and feel is so important with bread, rather than exact recipies. White French bread is very difficult, you really need an oven that runs hot and that you can get a blast of steam into to expand the dough and give a crackling crust. Anyone any experience with wood fired outdoor ovens? I've been planning one for years, but have never got around to it.