Well the whole project seems easy to me, but some parts of it is not clear, also it was better If you were attached APDL file as well.
you have asked for four changes to your current model
* first is “change input materials” , I assume you are going to change material property of plate or Pizoelectric material or both its easy part
* second is “change dimensions”, it's unclear if you want to change the size of the plate, piezoelectric or both, and how? or maybe I'm totally wrong and you want to do something else. Please explain more.
* Third part is “Control the right hand side edge properties...make them more gradual”, this part is also unclear whether the material is changing and you want it more gradual? or you want Mesh-size to change more gradual?
* at last the fourth part is “produce stresses along a curved path i.e. the circumference ”, its an easy task again, give me any path that you like and I will generate stress along that path.