Sanitary Y Tee Question
A Wye and an 1/8 bend, or a long sweep Wye gets the waste water going in the right direction. Those Tees are OK for vents, Not too good for waste.
I dont know when the change came about, but its a good one. I have opened up a lot of clogged up Galvanized Tee's over the years. Water running into the back of those just makes all kind of turbulence, and debris settles to the bottom, I guess. That cleanout should be turned up to a 45 degree angle too, IMO.
" A lot of men build things, and a lot of things fall down "