Cradler, dude, Anuj made a blog post that has a lot of the pistol squat stuff in it:
http://www.gustrength.com/anuj-train...of-progression
I don't know why he's holding out
Anyway, in the post he says that he didn't like using a box for various reasons. So I just wanted to defend the box a little. This has nothing to do with whether what Anuj did worked for him and pay attention to his progression in the post.
But I found the box perfect by simply perfecting one height and moving down the box. I didn't actually have to do it that gradually. That is not to say that it will work for everyone and there are more ways to skin a cat...just don't dismiss it out of hand.
It's a great blog post and there is a great discussion to follow.