There is backlash in a dividing head meaning that each individual part would need to be aligned horizontally, And then when indexing the dividing head, you would have to account for the error in the head, (that is backlash, imperfections in the head), which may not be good enough for the part. If you were to locate one of the upper internal flats of the internal square feature on a known height, known horizontally parallel to the surface table, all that you would have to do is calibrate your height gage mounted DTI and the check the lower internal flat for height and parallei, rotate, rinse and repeat.