Building (entirely) from @Ihatetomatoes demo, I was just attempting to apply a similar smooth scrolling effect on a page with pinned elements, but adding pinning seems to create some issues with the positioning of the pinned elements. I'm hoping someone has some experience with this and can point me in the right direction.
See the Pen MWbgRjy by january1979 (@january1979) on CodePen
Okay, I spent some time refining that demo and creating a helper function that should make this a lot easier for you and it does seem to integrate fine with pinning once I figured out that the jittery behavior was due to the fact that the ScrollTrigger wasn't being updated each time the fake smooth-scrolling tween was moving the content.
So here's a new CodePen that demonstrates what's possible:
See the Pen gOgWELo?editors=0010 by GreenSock (@GreenSock) on