the assembly doesn't necessarily have to be big. you could use a small setup and see how it works. a 6 inch movement may be a little much for a small setup depending on space. you could do a 4 inch movement.
depending on the actuator you may be able to do a 2 stage arm which will work the same way but be on the same plane as the coroplast. this may make it easier to mount. I think the big thing will be to get an actuator and play with it. I would think a slow moving solenoid would be best if you could find it.
here is yet another cheesy drawing of mine.