Iam planning a reno in a 2 storey century home. I am located in Ontario Canada and would like to get advice regarding installation of 2 water closets back to back on the 2nd floor , vented by the 3 inch stack vent. I have provided a diagram. Both toilets would be 12 inches away from wall and 3 inch vent runs up through 2nd floor ceiling and out through roof. Both water closets would drop into 3 inch horizontal waste pipe , run 10 feet along joist cavity then turn and drop to basement. I would like to know if this would be to code. I need to run the 10 feet horizontally to reach a wall to drop down through. Any help would be greatly appreciated.