Some pro advice would be greatly appreciated. Some basic info. Western NY area. 1 story ranch with finished loft (eventually). Crawl space foundation with no room to maneuver after subloor install. 2x6 ceiling rafters spaced 16. Kitchen area vaulted so no ceiling rafters. 3/4 inch coming from street. I'm quite sure I'm not explaining fully but here is my question. I plan to install a manifold system to take advantage of minimal connections. Manifold(s) will be located in same closet within utility room that contains hot water tank and main water valve. All lines can be run either below floor or above ceiling except for kitchen. Which would be more advantageous, or required by code? A further bit of info...all plumbing is very near center of house width wise (as per my plan) so there will be no long runs. The same applies to drains/vents. I'm new here and am fairly handy but my concerns are code and efficiency. I plan to do work myself and have inspection performed when work completed. Thanks alot. If more info is needed, please ask.