I give my players the traditional number, unless the player reminds me of a real player that I like. For example, I got an Argentine left footed MC Play-Maker for one of my teams. My initial reaction is "wow a Juan-Sebastian Veron copy!", and he get 8 like Veron. I got a german vet that plays MC, DC and DL, he got 21 like Philip Lahm. And so forth!