Copper has a different molecularity then your slate or glass or other metals, so naturally there are going to be some differences in the pot internals. Density of the pot is important, that is why I use Osage as my go to pot material. Thinner floor and outer wall thickness makes a difference too, if you are making pots with 1/4" thick floors try reducing it a little with the copper, your portal pattern is also important, as you are going to want a maximum effect when it comes to volume and not just on the loud end but with your purrs as well. Your ledge is going to be no more the twice the thickness of your copper, your pedestal walls should be 1/8" thick and large enough to secure the soundboard without losing vibratory qualities.....sound too difficult? Naw, just experiment till you get the right sound coming from the pot call.