A documentation of the exact content of carbon and other substances in the steel would be of good help in the choice of raw-material. I have taken some samples, but I have not had the opportunity to analyse them yet. The next step would be to get a steel mill to deliver raw material according to this specification and have a steel drum factory to produce high quality drums especially for steel pan making. Further measurements, stating within which ranges the content of the various substances could vary and still make a good instrument, could also give clues to which factors in the properties of the metal that are important to the tone generation. The thickness of the steel affects the resonance frequency of the note.
Thicker metal is stiffer and therefore it produces a higher pitch in a note with constant measures.
But thicker metal is also heavier. This lowers the frequency, which will counteract the effect of the stiffness. The acoustic effect of changes in thickness has to be measured to reveal what the net result will be. Suitable experiments would be to add chromium or grind off material successively and do measurements of the frequency spectrum. Another important acoustic effect of the thickness is that an increased mass can conserve a larger amount of energy.