I currently have two toilets that I need to replace. One appears to have an 11 inch rough in and the other has a 12 inch rough in. My current toilets clog up a little bit too easily. The one with the 11 inch rough in I don't use it all because it clogs constantly. My question, what should I replace it with? Elongated? Round? American Standard? Koehler? I basically just don't want to deal with clogs anymore. Help!