Set unique Scale to Instances

Check this example. it contains randomization algorithms for instances transforms.

https://forums.unrealengine.com/community/community-content-tools-and-tutorials/1491686-free-procedurally-instanced-meshes

How do I set scale for each instance when using “Add Instance”. I am spawning meshes in a volume and I’m trying to set the scale of instances closer to the centre to be smaller and the ones towards the edges, bigger. Any Idea how to do this?