Tom how are you today? I have to relocate my whirlpool tub from my orig. location. Will the overflow work as the vent for the drain? The drain line will travel about 10 ft. before I can tie in to the 3 in. waste line. And also, my drain lines for the vanities, can it by any chance dump into the 3 in. waste line by putting in a sanitary T in my 2 in vent for my toilet? In other words can I dump my vanity drain line into the 2 in. vent line that comes up the wall from my 3 in waste line? Hope I didn't confuse you like I am. Thanks Tom. I am kind of confused on how Im going to make this mess om mine come together. Shower system came together great though. Thanks again,Dave.