The point of PCT is to restore your natural testosterone back to normal after you come off cycle, Because when you start injecting/swallowing synthetic test your body stops producing its own hence the phrase "shut down"
But seriously have you considerd trying to gain the wieght naturaly?
Because i have trained a few aussie rules guys(im a pt) and i know you could gain those 5 kiolos just but training and eating rite, man obviously its your choice.
Good luck either way