Port definition after split

Hello guys,

I am simualting a gain horn with HFSS. To reduce simulation time, i decided to split the object.

My questions:

1. How should I draw the new Line for the Port definitions? Is it right on the screenshot attached?
2. I need to define symmetry planes for the split, with a rectangular waveguide there is a E plane symmetry and a H plane symmetry. How is it with cicular waveguides?

thanks a lot !

Sevdam