The cooling here needs some work . If this was mine here is what I would do . Those openings next to the spinner don't do much to help as is . I would close them off completely and paint them black . Now that there taken care of open up the bottom hole at the front .It needs to head towards the spinner . You want the air to hit the cylinder and be forced passed through the fins to carry the heat away . Thats why the top ones are near useless unless there baffled to force air down to the head . More often then not they just force air into the the cowl and it blocks more cooling air coming in where its needed ie, the head . One last thing dont worry that it may spoil the scale lines of the plane . YOU DONT want to COOK your beautiful engine . The late P E Rievers had a great set of pics explaining it on his website but since his death its no more . Maybe u could find it . Ive got them but cant upload them for some reason too easily . Try this first and then you can look into adding louvers if necessary . Cheers the pope