there are two reasons cones are usually sold in sets of 3. one is that the flat top surfaces of three cones determine a (flat) plane under the component whereas four cones can be a little bit wiggly due to imperfect flatness of the underside of the component. the second reason is that 3 cones almost always sound better than 4.. Flipping the cones over to tips up position won’t solve the problem of 4 cones since tips should always point down.
Lak - I always separate maple plates using DH Cones, as well as use DH Cones under component AND under the plate. If budget permits I use Supers, but if a more cost effective solution is required Large DH Cones work very well, and the Small DH Cones are not chopped liver. It goes without saying some springs should be part of the equation.