The typical rule is time on = time off. Time on is Cycle + PCT. So if you ran a 12 week cycle, with PCT.. you should be off for 4-5 months. You should always confirm with blood work that you are recovered before starting a new cycle.
There is too many variables involved to answer "what kind of gains should I get." Providing a little more info, like age, height, weight, and body fat. As well as your training schedule and diet.