its just a piece of sheet metal, don't overthink it. Cut out something that works, round the corners, drill holes that match the places to screw it in. As long as it draws air to the valve, you are fine, don't make it fit tight to the valve cover so any oil that goes in can drain back out. The rockers just fling oil around in the valve cover and you don't want it to get sucked right into the PCV
