Slightly off-topic now but do people allergic to nuts generally react to peanuts too, given than peanuts are not "real" nuts (are they more like peas?)
I can't imagine much of the active "nutty" compounds are left after a good heating at 250C in any case?
This rough vs smooth thing is something I havent worked out yet. I've had my DO about 3 years but I wet sanded it by hand with wet and dry when I got it inside and in the lid. Now it works OK but the seasoning does seem to be a bit fagile and hard to build up. I recently got a new skillet from clas ohlson http://www.clasohlson.com/uk/Cast-Iron-Frying-Pan/Pr342333000 sand cast and worked by hand and is much rougher but seem to be much better at holding it seasoning and is much more non stick!