In looking at the drawings, it seems fairly straightforward. Use a 3/4” straight bit (dado bit) and enough passes each to reach the shallowest needed dimension. A fence will be useful to guide the router base and likely need be moved to achieve the required width. Then use a narrower straight bit, adjust the cutting depth as deep as needed to meet the drawing dimensions. As you likely know the depth of cuts for the deep and shallow dimension will best be achieved in increments. Cutting a deep cut in one pass can be done, but likely result in tear out and/or other frustration easily avoided by taking multiple passes at increasing bit length.
An alternative approach would be to use a table saw and adjust fence and blade depth as needed. That likely would be my choice for speed and cut quality.
Both options will achieve a quality product if the boards are dry, straight, knot free, without bows, twists or other defects.
