How to change voxel size (NavMeshBuildSettings.tileSize)

Hi all, I'm trying to work with the advanced navmesh components. I am using the example of "localNavMashBuilder" and its working fine. My problem is that it uses a volume to calc the mesh which doesnt seem to sit to the cround properly. I think this is simply a matter of changing the voxel size but I cant find any examples of how to implement this change. I have looked up "NavMeshBuildSettings.tileSize" in unity manual but without an actual example i'm a bit lost. Can anyone please provide and example of how to set the voxel size at runtime?

I reckon its to do with "NavMesh.GetSettingsByID(0);"

Heres the code (latest from github):

using UnityEngine;
using UnityEngine.AI;
using System.Collections;
using System.Collections.Generic;
using NavMeshBuilder = UnityEngine.AI.NavMeshBuilder;

// Build and update a localized navmesh from the sources marked by NavMeshSourceTag
[DefaultExecutionOrder(-102)]
public class LocalNavMeshBuilder : MonoBehaviour
{
// The center of the build
public Transform m_Tracked;

// The size of the build bounds
public Vector3 m_Size = new Vector3(20.0f, 20.0f, 20.0f);

// Voxel sizing


public static NavMeshData m_NavMesh;
AsyncOperation m_Operation;
NavMeshDataInstance m_Instance;
List<NavMeshBuildSource> m_Sources = new List<NavMeshBuildSource>();

IEnumerator Start()
{
while (true)
{
UpdateNavMesh(true);
yield return m_Operation;
}
}

void OnEnable()
{
print("navmesh builder enabled");
// Construct and add navmesh
m_NavMesh = new NavMeshData();
m_Instance = NavMesh.AddNavMeshData(m_NavMesh);
if (m_Tracked == null)
m_Tracked = transform;
UpdateNavMesh(false);


}

void OnDisable()
{
// Unload navmesh and clear handle
m_Instance.Remove();
}

void UpdateNavMesh(bool asyncUpdate = false)
{
NavMeshSourceTag.Collect(ref m_Sources);
var defaultBuildSettings = NavMesh.GetSettingsByID(0);

var bounds = QuantizedBounds();

if (asyncUpdate)
m_Operation = NavMeshBuilder.UpdateNavMeshDataAsync(m_NavMesh, defaultBuildSettings, m_Sources, bounds);
else
NavMeshBuilder.UpdateNavMeshData(m_NavMesh, defaultBuildSettings, m_Sources, bounds);
}

static Vector3 Quantize(Vector3 v, Vector3 quant)
{
float x = quant.x * Mathf.Floor(v.x / quant.x);
float y = quant.y * Mathf.Floor(v.y / quant.y);
float z = quant.z * Mathf.Floor(v.z / quant.z);
return new Vector3(x, y, z);
}

Bounds QuantizedBounds()
{
// Quantize the bounds to update only when theres a 10% change in size
var center = m_Tracked ? m_Tracked.position : transform.position;
return new Bounds(Quantize(center, 0.1f * m_Size), m_Size);
}

void OnDrawGizmosSelected()
{
if (m_NavMesh)
{
Gizmos.color = Color.green;
Gizmos.DrawWireCube(m_NavMesh.sourceBounds.center, m_NavMesh.sourceBounds.size);
}

Gizmos.color = Color.yellow;
var bounds = QuantizedBounds();
Gizmos.DrawWireCube(bounds.center, bounds.size);

Gizmos.color = Color.green;
var center = m_Tracked ? m_Tracked.position : transform.position;
Gizmos.DrawWireCube(center, m_Size);
}
}