here's a bit of a trim template:
trim the upper part of the duct to pass the parking brake cable and accommodate the wheel. there are two small tabs to remove. the fastener closest to the hub works ok, but the one closer to the front of the car needs to be zip-tied together.
and yeah, it'll probably do more good to cool the cv's than the brakes. i think the two ducts on the tray under the transmission cool the inner cvs?