Placing an object on the side of another object?

Hello! I am working on a placing system for a game i am creating

The objects are going to be different shapes and sizes from one another, And these objects are going to 3D I'm trying to set the position of the selector on the side of another object And then i am trying to round the position for more a a grid-like placement

So far i have this code:

     public static bool editMode = true;
     public GameObject test;
     static Material selectorG;
     static Material selectorR;
     public static GameObject selector;
     public static bool canPlace;
     public static bool snapping = true;
 
 //This function is being called in LateUpdate()
 if (Physics.Raycast (ray, out hit)) {
             Vector3 hitSide = hit.normal;
             selector.gameObject.SetActive (true);
             Mesh model = go.GetComponent<MeshFilter> ().sharedMesh;
             selector.GetComponent<MeshFilter> ().mesh = model;
             Vector3 newPos;
 
             // Setting the position of the selector
             // If snapping is disabled
             if (snapping == false) {
                 //This works
                 newPos = new Vector3 (hit.point.x + Mathf.Ceil (hitSide.x) / 2, hit.point.y + 0.001f + Mathf.Ceil (hitSide.y) / 2, hit.point.z + Mathf.Ceil (hitSide.z) / 2);
             // If snapping is enabled
             } else {
                 //This doesn't work.. Instead it floats off the ground, And if you put your mouse against the wall, It will float off the wall too
                 newPos = new Vector3 (Mathf.Round(hit.point.x + Mathf.Ceil (hitSide.x) / 2), Mathf.Round(hit.point.y + 0.001f + Mathf.Ceil (hitSide.y) / 2), Mathf.Round(hit.point.z + Mathf.Ceil (hitSide.z) / 2));
                 // And the other way of doing this..
                 //This doesn't work because it intersects the object it hits, And i want it to be rounded..
                 newPos = ray.origin + (ray.direction * hit.distance);
             }
             selector.transform.position = newPos;
             selector.transform.localScale = localS;
 
             //Setting the material accordingly
             if (canPlace) {
                 selector.GetComponent<Renderer> ().material = selectorG;
             } else {
                 selector.GetComponent<Renderer> ().material = selectorR;
             }
             //Rotation.. Ignore this
             if (Input.GetKeyDown ("q")) {
                 selector.transform.Rotate (Vector3.up * 90);
             }
             if (Input.GetKeyDown ("e")) {
                 selector.transform.Rotate (Vector3.up * -90);
             }
             // Placing the object when you click the mouse
             if (Input.GetMouseButtonDown (0) && canPlace) {
                 GameObject newObj = Instantiate (go);
                 newObj.transform.position = selector.transform.position;
                 newObj.transform.rotation = selector.transform.rotation;
             }
         } else {
             //Making the selector disappear when there is nothing the mouse is hitting nothing
             selector.gameObject.SetActive (false);
         }
     }

And from line 48 to 59 i am setting the position

             Vector3 hitSide = hit.normal;
             if (snapping == false) {
                 //This works
                 newPos = new Vector3 (hit.point.x + Mathf.Ceil (hitSide.x) / 2, hit.point.y + 0.001f + Mathf.Ceil (hitSide.y) / 2, hit.point.z + Mathf.Ceil (hitSide.z) / 2);
             // If snapping is enabled
             } else {
                 //This doesn't work.. Instead it floats off the ground, And if you put your mouse against the wall, It will float off the wall too
                 newPos = new Vector3 (Mathf.Round(hit.point.x + Mathf.Ceil (hitSide.x) / 2), Mathf.Round(hit.point.y + 0.001f + Mathf.Ceil (hitSide.y) / 2), Mathf.Round(hit.point.z + Mathf.Ceil (hitSide.z) / 2));
                 // And the other way of doing this..
                 //This doesn't work because it intersects the object it hits, And i want it to be rounded..
                 newPos = ray.origin + (ray.direction * hit.distance);
             }

All help is appreciated :)