Here is another article on manipulation that was posted on Michael Agneta’s site last year. It’s a good read.
Great stuff. There have been a number of threads here talking about similar things.
I like how he notes he presents the same water from different angles. I fell that it alone can make a huge difference, in addition to manipulations. It is why what we do is often called angling. Presentation angle can change a lot of things, the biggest one is working depth and swing trajectory. Sometimes the vertical swing/rise, sometimes a cross current swing. I have to work on improving my up current presentations. They are often the most difficult for me to finesse .