Sexuality has multiple axes.

1. Intensity
2. Orientation (towards Men, Women, Frogs)
3. Time (people have been known to have straight periods, gay periods, horny periods, ace periods, etc.)

There are probably others that we relate to kink and paraphilia.

So the very gayest person would have to be specifically defined. Which is gayer: the horniest bisexual or the average-libido gay who has absolute-zero-Kelvin interest in the other sex? Or the gay man who is totally in love with (and exclusively devoted to) his hubby and has been this way for fifty years?