Whether you are dancing at a ball or just in class, once you get 'good' at it the dancing turns into sweaty work.
I would say get yourself a lighter but well made PV or Acrylic for the classes and keep a tank for the fancy balls.

A lot of folk in your class might wear trousers when they are practicing. That needn't be the case.
You can be the one to get them wearing their kilts more often!