As I mentioned above, I have three PolyMetric transfer fixtures that support two faceters in my shop. However, I don’t use indexing when transferring.
I simply set the index at one of the girdle facet indexes and the angle to ninety degrees… leaving the dop setting “loose” in the quill. I then gently lower the head until the girdle facet just touches a master lap. Since the stone is not tightened in the quill, one can simply hold the stone in position and secure the dop in its new position, perfectly indexed.
If, by chance, I very slightly misaligned the dop, it is easy to identify and correct. Simply make a cut at the first P1 facet (SRB). As the facet is approaching the girdle one can see if it is not perfectly aligned with the girdle facet. If so, simply “tweak” the cheater a bit and continue cutting… that “tweak” will remain in place for all the crown facets to follow. While seldom necessary, this double-check will become second nature as one gains experience.