Two models from one Image Target - localPositions

I have modified the sample DynamicDataLoader script to load my dataset and attach 3D models to trackables. Some of my image targets get two augmentation objects attached to them. My aim is for these to be offset from each other, so they don't overlap, but my attempts to do this using their transform.localPosition's haven't worked so far. When I put a negative offset for one and a positive for the other for the x or y component of the localPosition, the objects completely overlap. When I put the offset in for the z component, the objects are offset in what I thought was the y axis. Any thoughts?

// Iterate over molecules to add to trackable. Paired molecules will result
// in a pair of molecules being parented to trackable.
    for (int molNumber = 0; molNumber < moleculesToLoad.Count; molNumber++)
    {
     Object augmentationPrefab = Resources.Load("Prefabs/" + moleculesToLoad[molNumber]);

        if (augmentationPrefab != null)
        {
         // instantiate augmentation object and parent to trackable
            GameObject augmentation = (GameObject)Instantiate(augmentationPrefab);
            augmentation.transform.parent = tb.gameObject.transform;
            augmentation.transform.localPosition = new Vector3(moleculeOffset[molNumber], 0f, 0f);
            augmentation.transform.localRotation = Quaternion.identity;
            augmentation.transform.localScale = augmentationObjectScale;