Convert BuiltIn array to an Generic List?

OK this one has me stumped.

I have a game object with the script below attached. The script works fine, It provides a BuiltIn array list of splines in the inspector window and on runtime the gameObject will travel along a spline and when it reaches the end of the spline, pick another random spline in the array list and travel along that one etc.

What I want to do is to declare a Generic List instead of a built in array so I can then Add() and RemoveAt() splines within the array at runtime. I know this can't be done with a built in and am struggling to find the correct syntax to do so.

I know it would be something like..

           public List <GameObject> splineArray = new List <GameObject>();

…but I also need to include the type Spline in there somewhere. Maybe this is the wrong way completely and I need to convert from builtin to a list at runtime and then back again, as I said I am stumped :-)

Any help/ideas/direction would be really appreciated.

Thanks.

using UnityEngine;

using System.Collections;

using System.Collections.Generic; // Added here for the Generic List

//This class animates a gameobject along the spline at a specific speed.

[AddComponentMenu("SuperSplines/Animation/Regular Animator")] public class SplineAnimator : MonoBehaviour {

 public Spline[] splineArray;
 private Spline spline; 

 public GameObject prefab;
 public WrapMode wrapMode = WrapMode.Clamp;    
 public GameObject go;    
 public float speed = 1f;
 public float offSet = 0f;
 
 static float passedTime = 0f;
 
 void Start() {
     spline = splineArray[Random.Range (0, splineArray.Length )];
 }

 void Update( ) 
 {
     passedTime += Time.deltaTime * speed;
     
     float clampedParam = WrapValue( passedTime + offSet, 0f, 1f, wrapMode );

     //Interpolate a custom value according to the interpolation type and spline settings
     //The custom values can be set in the SplineNode scripts or in the inspector
     float customValue = spline.GetCustomValueOnSpline( clampedParam );

     transform.position = spline.GetPositionOnSpline( clampedParam );
     transform.rotation = spline.GetOrientationOnSpline( clampedParam );

     go.renderer.material.color = Color.white * (1f-customValue) + Color.black * (customValue);

     if (passedTime > 1f) {            
         passedTime = 0f;

            // complete a spline and then pick a new one from array
         spline = splineArray[Random.Range (0, splineArray.Length )];
     }

 }
 
 private float WrapValue( float v, float start, float end, WrapMode wMode )
 {
     switch( wMode )
     {
     case WrapMode.Clamp:
     case WrapMode.ClampForever:
         return Mathf.Clamp( v, start, end );
     case WrapMode.Default:
     case WrapMode.Loop:
         return Mathf.Repeat( v, end - start ) + start;
     case WrapMode.PingPong:
         return Mathf.PingPong( v, end - start ) + start;
     default:
         return v;
     }
 }

}