I would put all 6 SP into Stamina. It's a point where you are no longer getting good value for training it and WRs need stamina to run top speed for the duration of the play for the entire game.
Train some of your higher skills, like jumping+vision. It may seem counter-intuitive, but training skills right after you've capped them bring a nice return (remember that these skill are worth 2, 3, 4 SP's etc....)