Hello I am removing a tub and replacing it with a prefab shower base and need some drain and waste help. I have good access underneath. Existing is a 3" copper waste pipe and I was thinking that I could cut a small section out and install a 3x3x2 sanitary tee to pick up the shower and cap off the exisitng 1-1/2 which is further up line but wasn't sure how to go from copper to pvc thank you