Here is a link to the Youtube video that shows how to mark your leader centers after they are on the frame:
https://www.youtube.com/watch?v=Q3b3E6RlLyM
I believe this is the same woman who developed and sells Red Snappers. One reason I am planning on getting Red Snappers rather than Leader Grips is because with the Red Snappers, the part that snaps on to the rods is flexible. On her website she shows how you can flex that part back to open up the gripping area to make it easier to get them on the rods. With both types, I have read they are hard to use at first and then loosen up with use.