Hint: When selling a Hydro System Freestanding Tub, Hydro System can send a floor template ahead of the tub.  Use the template to map out the drain location.  Then use an OS&B ITD5135 Island Tub Drain to set the rough.  This will allow the plumber to do their part and allow the project to move forward all the way through tiling before the tub is needed on site.