You asked for the most efficient and easy to handle taht makes a good end result*. Not easiest to make.
since each pedal would just morph between 2 states?
Nothing says so they can morph between X sattes. The blendshape tool is often misunderstood because the GUI isnt powerful enough to describe all it can do.
Yes lot of people claim it can just do linear moves. Thats sort of true, but hey even a nurbs or bezier curve is just a bunch of linear moves multiplied by a nonlinear constant. So in a way even curves in 3d software are mostly based on linear moves. But at the end of the day that means you can have nonlinear moves with blendshapes for the same reason. Sure the GUI doesn't help you sort that out. But thats no reason to say theres nothing in the blendshape node that say you cant do this.
in any case blendshape has a special axis for making one blend actually consist of many sequential targets, its just a buit hard to get done in a GUI except for one blend axis. However the script interface allows you to define as many axes as you like.
*best is not defined. it depends on stuff that i can not know about you.