Hermione, thanks for the links.
I asked about the number of culminating stars because there is some confusion in this matter.
In some documents, Bauval mentions the culmination of Kochab only (for example, Bauval & Gilbert "The Adze of Upuaut: The Opening of the Mouth Ceremony and the Northern Shafts in Cheops's Pyramid", DE 28, 1994).
In the pdf-version of his book "The Orion Mystery" (1994), the culmination of Kochab only is mentioned (Appendix 6, Appendix 7), while Plate 15a is missing.
However, the simultaneous culmination of both Kochab and Mizar is depicted in Diagram 2 in his article "The Logistics of the Shafts in Cheops' Pyramid" (DE 31, 1995).
It should be taken into account that Bauval's vertical, Kochab at upper culmination - Mizar at lower culmination, precessed to the west from due north with time, while the pyramids of the main azimuth trend (from pyramid of Meidum to pyramid of Neferirkare) deviates to the east from north with time, therefore, only the reverse configuration (Spence's vertical) of these two stars is suitable to explain orientation of the main trend pyramids: Mizar at upper culmination - Kochab at lower culmination.
It is interesting that Belmonte in the article "On the orientation of Old Kingdom Egyptian pyramids (2001)" also mentions the wrong configuration of the stars: (p. S3) "Granted this, the orientations of the pyramids implied that most of them would have been aligned with Mizar at lower culmination, but the pyramids of Khafre and Sahure would have been aligned with Kochab at lower culmination".
Alex.