The only way to know for sure when you are ready is to have blood work done. Everyone takes a different amount of time to recover. The basic guide line that you'll hear online is cycle length, plus PCT = time off. So in your case, using that method, after PCT, you would wait 18 wks for your next cycle. I'll be honest, I don't wait that long but I do get my labs done regularly and keep my health in check. Each time you go "on", you shut down your HPTA, and if you aren't giving yourself enough time to recover, you'll make it harder and harder to recover in the long run. For someone that is a pro with a career in the sport, it may be worth the risk of never fully recovering. Your ROI is a lot less, if your goal is to look good on the beach and out lift guys in the gym.
BTW, I would be sure to give yourself about a wk before you start PCT after stopping the Prop. Even though the half life is only a few days, I have tested at +1500ng/dl 5 days after stopping TNE. I'm sure prop will keep your levels up longer.