you need to re-upholster your head rests with the frame integrated so you can just mount it to that with a "flush" look.... it really shouldn't be much money to get both head rests done just go to a local upholstry shop, doesn't have to be a car shop and tell them what you are thinking i am sure they will be able to help out...
o btw...good luck with what ever you do man... love the headrest screen look...