This method is 100% taken from the Novabeast Substance Painter file but I want to archive it somewhere
<aside> ⚠️ You need to make sure you have baked most Mesh Maps on your model before applying the layer effects
</aside>
You can try inverting the light effect to make a fade from the tips for example!
The Fill map contains the AO map
https://public.sesilaso.com/WikiStatic/Hair Highlights.spsm