This weekends project is to finally hook up my ro/di after moving 2 years ago lol.
Here’s a picture of some drain lines I have accessible in the basement. I am assuming that I want to tap the drain above the p and s traps for my drain saddle, right?
If those drains are your options, I would drill and tap that upper clean out cap. Installing a threaded to push connection that would fit your RO drain line. I personally would not use a saddle.