Good question. Its a lot easier to go from long acting to short. I would begin the transition by running 1/2 of your cyp dose with 1/2 of your prop dose for about 10-14 days, then increase to your full dose of cyp while reducing the prop by 50% again for another wk or so. You might feel a little dip but there is no perfect transition. It should be pretty smooth and you should be able to continue growing.