Cut, assemble and install the two plate rack "ladders." Use short screws to secure the ladders in the cabinet opening. We set the rear ladder 4 in. away from the back of the cabinet and the front ladder snug against the back of the face frame.
Have you ever considered using that wasted space UNDER your cabinets? Hidden by that toe kick panel is a goldmine in terms of storage space. Add some short custom drawers to store things like cookie sheets and muffin tins. Woah!