Well we went for the door crack step. He had one hiss at the beginning. The door has a gap of about an inch at the bottom and I opened it wnough that they could bat each other if they wanted. They played batting a ball back and forward with paws under the door. Then he went for a pee ad she wandered off. We opened the door enough for them to get through the door and neither of them were interested. He was playing with a fly and she went off with the ball. Here I was scared to death about this.
There are many intelligent species in the universe. They are all owned by cats!