Image sequence by scroll position problems

[thehappyappy]

Please can somebody help me, I’ve added the ScrollMagic to a site I’m working on because I want to have an animation controlled by the user scrolling but I’m having a little bit of trouble with it. I’ve got it all working but if somebody scrolls really quickly the animation scrolls too quickly, ideally I’d like to set the fastest speed it’ll animate at but have no idea how to do that so would be grateful for any help, please.

If it helps the animation can be seen here: http://www.akaillustration.com/indexNEW.php 1 (its the delight clients animation on the right when you scroll down).

Thanks in advance.