I changed the layout of my bathrooms a bit because they were originally slightly too large. I created a space between the restrooms which acts as a mechanical room and makes and service that the plumbing system might need easier. My restrooms were already stacked on top of one another which made it pretty easy to connect the systems. The only issue that I really came across was creating each branch of the system and connecting them to the central pipes that ran vertically through the building, but I realized that when I changed the order in which I placed the pipes the issue was resolved. I used 1” pipes for the cold and hot water systems and 4” pipes for the sanitary system.