Boudreau coached the PP in Minnesota. He liked having 2 units and even claimed that staying more than 1 minute on the ice is selfish. In Minnesota he had the Staal and Koivu units and would equally start either.
He actually talks in this podcast in detail about his powerplay philosophy and how he likes to set up based on the type of personnel available. He also reminisces about his PP in Washington. It's quite a detailed and technical discussion.
At the very start at the podcast: