I'm a relative Blender novice, but I've started using Geometry Nodes to generate a roof from a single roof tile mesh, adding randomisation to the position and rotation of each instance to create a somewhat jumbled, hand-made appearance:
This is done using what I imagine is a pretty clunky set of geometry nodes that I've made through trial and error:
What I want to do, but have so far failed to achieve by trial and error and internet searching, is to randomly tint the colour of each tile instance by varying the value of the material colour ramp factor for each instance, but I can't work what node to use, nor how or where to insert it into the node tree to affect individual instances:
Any help would be gratefully received. I've uploaded a copy of my Blender file here.