At the beginning of Kedusha, the Chazzan says v'kara zeh el zeh v'amar. I've seen three types of chazzanim with regard to bowing left at the first zeh and right at the second:
- bow left and right at vkara zeh... every time.
- never bow at vkara zeh...
- bow left and right at vkara zeh, but only on Shabbos.
Which is correct, if any? And if this bowing is correct, should a non-Chazzan also do it?