I agree with P-22. I have one big cycle a year now, which is only topped up with much shorter "maintenance' cycle. This works much better for me than constantly cycling on and off. Then again I don't compete, so another method may work better for you.
How long do you stay off? What are your goals? Do you want full recovery to baseline? Then you need bloodwork prior to the cycle, and you need to get it done every 3 weeks until you are back to where you want it. That will be an individual thing, and "XYZ# of weeks" isn't going to tell you if you're 100% recovered.
On the other hand, if your goal is to recover to within normal (acceptable) parameters (which could still be 13rd of YOUR starting level)- then you need to get bloodwork also, but could probably stop PCT alot sooner.
I usually say if you are running an aggressive PCT (read: mine), you can get away with 1/2 the time off as time on. If your PCT is garbage, then you need double the time off as time on.