You asked an impossible question to answer. And then you want the impossible by wanting guaranteed gains. Sorry, but you may have done some reading, but there seems to be a fundamental lack of putting this information together. Oh wait, I forgot, before every basketball game, instead of practicing free throws and jump shots, the athletes are on the court getting their hormone levels checked so people know how much gear to use.
Cyp is good, nothing wrong with it at all, it is a great ester for test.
As for your impossible question, you neglected to state what kind of athlete, marathon runner, olympic level, high school level, football player, etc. And also, if it is his average without gear, then what makes you think he could have achieved what he has done without exognous test, plus any other a.s. he may have ingested.
And also, it's an irrelevant question. Since the average male has something like 80mg/test floating around in him per week (and this number is sometimes in dispute since it does decling with age, etc.), if you approach this level, your body will compensate and shut down your natural test levels.
I fail to see the fundamental reason why you asked this question.
Please don't take this as a flame, because this is not my intent, I am just trying to point out the problems with what you are asking, and how they don't pertain to exogenous gear use.