There is no "peak" time for training, it can be done at any time and up until about the second or third week of flowering, depending on flowering speed.
It is best to do a little bit often, rather than a whole lot all at once, which is taxing on the plant.
Also, try not to defoliate, it is unnecessary except in extreme cases of excessive humidity.
Just remember, -
Less leaves = less energy being made = less growth.
It really is that simple.