so the script for knockback can be found on voiceunrelentingforce3 magic effect form,

but is there a way to script a regular "stagger" effect?

my destruction spell magnitude scales with skill and level, and the attached PerkImpactStagger effect also scales along with it, which ends up making the spells overpowered as destruction skill goes up.

i would prefer to add a scripted effect to the spell that gives a set, small amount of stagger to keep it balanced and won't scale with mod spell magnitude perks.

Find the stagger (I think it's named stagger_start or similar) animation in Animations and use http://www.creationkit.com/SendAnimationEvent_-_Debug with the stagger animation. It will not only play the animation but also apply the 'stagger force' to the actor. Alternatively you could try using http://www.creationkit.com/PushActorAway_-_ObjectReference.