1. What is going on at A??? I can't envision what that is.
2. Could the double fixture fitting at the lower E move up (one of the Es was supposed to be a D) The standpipe could be 18 inches tall, I think.
3. Upper E and C are going to be combined as vents up higher, right?
4. B needs to be a long sweep because you are going from vertical to horizontal.
Alright, thanks. Please note that the photo you marked was an example of what I was considering, but have chosen not to pursue because I don't like the diagonal cuts through the studs for 2" pipe. It was the genesis for the original post question in this thread. The second picture in this thread was a possible solution to keep this 2" pipe inside a single stud bay. Possible? Nevertheless, your response has been helpful because it made me think about the LT connection.
1. In this photo, "A" is to service the Laundry Tub/sink. It is a san-tee with a street 90 coming out the tee's top opening. I wanted to add an extra cleanout below the LT. The top opening is for the cleanout and the bottom is for the drain arm. With my particular sink, it's not really deep like a normal LT, so I routed the drain/CO into a vertical position. But, as I think about it, maybe someone in the future may want a deeper LT. In this case, I may use a combo fitting and the street 90 to make it horizontal (keeping the connections lower inside the LT cabinet).
2. Yes, I can raise/lower the back-to-back fitting. This was a dry fit mock-up for DWV work and I included in-wall pipes/connections for illustrative purposes.
3. Yes. For a larger context and the bigger questions (this thread was meant to identify CW standpipe design possibilities), please see and feel free to critique the larger job, here -
https://terrylove.com/forums/index.php?threads/dwv-project-how-does-this-look.66185/#post-493543
4. It's just the picture angle, but "B" is a long turn 90.