Renovating my house and re-doing rough plumbing in bath. Purchased a European Duravit sink that is very narrow depth basin (6") , rectangular and sits on chrome legs with no vanity. My plumber (here in LA) says that he usually sets drain line in wall for trap at 18"" height from floor. I think this will be low and ugly as the pipes will be well below bottom of sink. Is there any reason why I cannot have him set drain line height at 24" from floor?