Re; cone rattles - a friend who owns a Beltona tricone (a high-quality instrument) was recommended by the maker to use a thin layer of Pritt-stick adhesive under the cones; it's a low-tack adhesive, & easy to remove later on, if necessary - unlike the cretin who used silicon sealant on the cones of my own 1930 National, thus making it impossible to remove them without terminally damaging them...oh, how we laughed..