How to add picot edging

I want to add picot edging to the opening of a shrug. I’ll pick up stitches around the opening. Now, I’ve read some different patterns online for items that have picot edging and they are all different!
So, does how many sts you bind off and how many you cast on and then bind off depend on how sts I have picked up? Or are there different types of picot edging?

I don’t know if this helps you, but I found this picot edging tutorial on youtube: http://www.youtube.com/watch?v=NAEMrlNNioE
It seems pretty easy, and doesn’t seem to change based on how many stitches you’re picking up to start with.