Customizing the new terrain system

I have been reading a lot about the new terrain systems in 2018.3 and it has mostly been introduction for these tools. I was wondering if we could customize it via scripts to suit our own use cases and how to go about it.

I should probably mention that I am a beginner in Unity and in game development.

Specifically I was wondering if we could do a low poly style terrain with the new system. I am currently working on a game with a hexagon grid based terrain similar to endless legends game. At the moment I am procedurally generating the mesh and calculating for stitching the terrain chunks. I haven't included any GPU instance based stuff as I am not very familiar with it. So I am also curious if the GPU instancing of terrains would also benefit my use case.

With Regards,
Pranav S K