Do I interpret your words as comparing similar diameter cones on a beam balance - some impregnated pulp and goop covered cones will be heavier than some thin poly cones for the same diameter? If so, can that necessarily dictate Fs? With the same surround, the same suspension, the same voice coil and former you can expect the mass to determine the Fs, but it doesn't necessarily follow, does it? The heavier cone could just as well be supported by a stiffer suspension and surround making it a higher Fs driver than the lighter cone, no?

It seems to me there has to be a far more complex relationship for there to be a preference; that many other physical parameters have to be considered in addition to mass alone including the combined +/-kX aspect.