Abstract: Circuit boards for lighting systems have identical LED landing zones printed on the board. Each zone includes at least two sets of LED contact pads. One pad set is configured to mate with contacts of an LED of a first structural type, e.g. from a first product line or manufacturer. The other pad set is configured to mate with contacts of an LED of a second type, e.g. from a different product line or manufacturer. The layout may enable an easy system re-design, e.g. to shift from one type of LED to another. Alternatively, the layout may enable one system to use LEDs of the two different types in a single LED set or array. Exemplary systems disclosed herein include an element for mixing light produced by LEDs mounted to the landing zones, such as an optical integrating cavity.