How do I persist data from a custom inspector for a list? (C#)

Hello! In my project, I have an object with an EnemySpawner script on it. This script stores a list of EnemyInit objects, each of which stores a GameObject for the enemy itself, a Vector3 for its starting position, and a Bool to indicate whether it faces left or right at the start. I have set up a custom inspector for EnemySpawner, which allows me to input all of this data for each enemy, and also choose the number of enemies.

This all seems to be working, until I actually run the game. When I do, the data all resets to the defaults, with no GameObjects in the fields, (0, 0, 0) Vector3s, etc (although, oddly enough, the number of enemies remains correct). I assume this has something to do with me adding and removing elements from the list in the inspector script, but I don't know how else to change the number of enemies from the inspector. Does anyone know what I might try to solve this? Here are the two scripts:

EnemySpawner:

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class EnemyInit {
     public GameObject obj;
     public Vector3 start;
     public bool faceLeft;
 
     public EnemyInit(GameObject _obj, Vector3 _start, bool _faceLeft) {
         obj = _obj;
         start = _start;
         faceLeft = _faceLeft;
     }
 
     public EnemyInit() {
     }
 }
 
 public class EnemySpawner : MonoBehaviour {
     public int enemyNum;
 
     public List<EnemyInit> enemies = new List<EnemyInit>();
 
     // Use this for initialization
     void Start () {
         for(int i = 0; i < enemies.Count - 1; i++) {
             GameObject enemyCurrent = Instantiate ( enemies[i].obj, enemies[i].start, Quaternion.identity ) as GameObject;
             if ( enemies[i].faceLeft ) {
                 enemyCurrent.transform.RotateAround( transform.position, Vector3.up, 180 );
             }
         }
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 }
 

EnemySpawnerEditor:

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 using UnityEditor;
 
 [CustomEditor(typeof(EnemySpawner))]
 public class EnemySpawnerEditor : Editor 
 {
     public override void OnInspectorGUI()
     {
         EnemySpawner myTarget = (EnemySpawner)target;
 
         myTarget.enemyNum = EditorGUILayout.IntSlider ("Enemy Number", myTarget.enemyNum, 1, 10);
 
         while (myTarget.enemyNum > myTarget.enemies.Count) {
             myTarget.enemies.Add(new EnemyInit());
         }
         while (myTarget.enemyNum < myTarget.enemies.Count) {
             myTarget.enemies.RemoveAt(myTarget.enemies.Count - 1);
         }
 
         EditorGUILayout.Space ();
 
         for (int i = 0; i < myTarget.enemyNum; i++) {
             EditorGUILayout.Space ();
             EditorGUILayout.LabelField("Enemy " + (i + 1));
 
             myTarget.enemies[i].obj = (GameObject)EditorGUILayout.ObjectField ("Enemy Object", myTarget.enemies[i].obj, typeof(GameObject), false);
             myTarget.enemies[i].start = EditorGUILayout.Vector3Field ("Starting Position", myTarget.enemies[i].start);
             myTarget.enemies[i].faceLeft = EditorGUILayout.Toggle ("Facing Left", myTarget.enemies[i].faceLeft);
         }
     }
 }

Thank you to anyone who has an idea of what I could to to fix this. I have a feeling that I need to approach the whole thing in a different way, so that I don't have to change the list in the editor script, but I can't think of another way to do what I'm trying to do.