Disclosed are methods for arranging passenger seats and passenger service units in aircraft cabins as well as locating devices used in these methods. These methods and devices provide fast and efficient ways for directly referencing the position of each passenger service unit relative to a corresponding passenger seat. For example, a passenger seat is positioned on a seat rail using rail markers. Each set of markers corresponds to a different seating configuration. A locating device is then placed on the passenger seat such that the device datum contacts the seat cushion. A locator of the locating device determines a reference, in an overhead compartment, for installing a passenger service unit, corresponding to this seat. The reference is based on an angle between the datum and the locator, which is adjustable in some examples.