[tzs]

What I'm suggesting is that maybe what matters is the total set of questions asked by all the interviewers. Does it really matter if one person asks questions for 2 hours as opposed to 6 people asking questions for 20 minutes each if the same questions are asked?

The former gives more flexibility to alter the questioning on the fly, such as to delve more deeply into some area than had been planned. The latter gets more people to spend time with the candidate.

A mix of this could be the best of both worlds. Have several short interviews mixed with some long ones. If one of the short ones turns up something that seems worth going in depth on that can be handled in one of the long interviews.