These minor movements are essential for realism. I try to include them even at 12 fps. Whilst I agree it's difficult to go as far as a cough or nose rub, it is possible to include the gentle shifts of balance and adjustments we all make all the time. Okham's 'Naturalizer'script (check the archives) is a usefull tool for this. Personally, I create the main pose and then go back to add the finer movements - to everything! Incidentally, Mimic defaults at 12 fps. Then again all my animations end up on the web so file size is a huge factor, if you've got the luxury of a large file size then by all means go for more fps, it'll be all the smoother for it.