I thought it would be more plausible and probably more interesting to do this in maybe 40 questions. To do this in 33, as several others have pointed out, would

I thought it would be more plausible and probably more interesting to do this in maybe 40 questions. To do this in 33, as several others have pointed out, would require 33 questions that each almost perfectly bisect the population and are almost perfectly independent of each other. With 40 or 45, we could relax that a bit and use questions that are actually meaningful. Two people who are within a few bits of each other would actually be similar in ways we care about, unlike two people who are similar because their transliterated last names both appear in the last half of the alphabet.