I have played around with a couple of our other dogs and found out it is not for every dog.
Fusion is just starting out on plank work. She tends to come off of the sides at times, so I decided I would put up x-pens on either side. I move them away from the plank more and more in each session. I am just working on her running, not pouncing, as she is doing the plank. What I am looking for is that her back feet are separated when they push off of the plank each time. I am very happy with it and will quickly fade out the x-pens so that I can raise the plank.
I am very happy with Risk's progress. I knew she would progress faster than Fusion because she has many years of dogwalk training. She also did "see wood run" as a young dog. I was able to raise her plank up to about 8 inches after warming up with it on the ground.