I would get as much media as possible. In my wet dry I have bio balls then below them I have 25lbs of ceramic rings, followed by 12lbs of sintered glass balls. You can never have enough filtration IMO and with how much rays cost spending a little more for the media shouldn't really matter.
Also it wont be fluidized and airstone cannot move the ceramics as they are to heavy. The extra oxygen will help more BB colonies form I believe so it will still be beneficial as wll as when the bubbles break the surface the oxygen then moves to the bio balls which helps as well.