I am doing the rough in plumbing in my barn for a bathroom (vanity, toilet, shower) my questions are how close should I bring my 4" main waste line to my first 3" wye or does it not matter? Can I have a elongated 90 in my main 3" line, I need to go 4" to a 4" 45 then my 3" needs a 3" 90 all in slab or should I avoid 90's until in put my pipes up my wall? I am currently working on a layout in my head that I will poast later.