I have a question, I need to lower the Sanitary T due to new sink being lower and garbage disposal out being lower then the wall out. Luckily the pipe is vertical in wall. The old T that you see in picture, is 2 inch coming from basement, 2 inch to kitchen sink and then 1.5 inch up to upstairs bathroom sink.
My new sink is lower and is only a single drain now instead of a dual sink.
How is it best to glue these new pipe fittings together if there is not much play to them. To ensure enough of pipe gets into the fitting. (Glue the New T First), then use a hard coupling 1.5 inch to the old 1.5 inch to upstairs?