I have a old building with a stone foundation where I might want to add a bathroom at some point in the future. There is a sewer stub ten feet from the side of the building. I'm in the process of extending the sewer stub and entering through the side of the building's basement foundation. I have a question on the correct method to transition from the 6" SDR-35 sewer pipe to either a 4" PVC or ABS drain line. What is the recommended transition piece and where should that transition take place?