Like said, a strong PCT as laid out here ^^^, will enhance your body's ability to recover and realize a natural hormone balance, but keeping your gains is going to have at least as much to do with your diet and continued hard core training.
this is all a hypothetical question because it really depends on YOU... it depends on how you eat and train after and if your running an extensive pct and doing the right things in between cycles... run a sarms bridge after you complete pct and you will not only keep gains but clean them up and add to them... here is a strong pct for you and then a sarms bridge as well...