As a bisexual male here's what I have to say about it, at least from MY own personal experiences.
I can’t really box my sexuality into a number, percent, or ratio; but I just know what I like and what I don’t like. I don't really see myself in ratios/percents in the whole gay/het dichotomy. I just go by the fact that I've been sexually and romantically attracted to both men and women. I've met people who think of their bisexuality in the whole het/gay dichotomy (i.e.-80% het, 80% gay) but I can't do this and I have absolutely no idea how people can come up with ratios like that with something so complex as human sexuality, let alone their own sexuality.
I can't really go by the Kinsey scale, because I've been at different points on it with different people. I don't really go by the Kinsey scale because it just measures past sexual behaviour, not desire. I have been all over it, and fallen in love with both men and women. I have found that most people rate themselves too low. For example in the original study if you were a "1" on the scale it just meant that you had sex with someone of the same gender while drunk, if someone was forced to do it, or just once out of curiosity and never again such as how lots of guys that grow up to be het are sexual with boys as a kid and masturbate together or "experiment".
I also think that the scale is out dated in today's fluid sexual society, where our definitions of orientations are changing and becoming obsolete; but I see just why the study had to be researched/published in a time when all sexuality was "in the closet" so to speak.
The Klein grid (see here:
http://en.wikipedia.org/wiki/Klein_Sexual_Orientation_Grid and here:
http://www.youthnetsouthampton.org.uk/breakout/kleingrid.php) makes sense to me but I don't obsess over what my number is, and last time I took it, it said that I was mostly equal but a bit more into men. I've had times where I've thought that I'm het and times where I thought I was gay but I know that I'm neither, and that I've never been heterosexual even if society tries to program us into thinking that we are that way.
I do know that it all boils down to the person. I'm attracted to people for things that don't have to do with their gender such as intelligence, humour, personality, communication, our personal chemistry, kindness or other aspects that have more to do with who they are as a person than their gender. The more I get to know a person on a personal/intellectual level the more I'm attracted to them, and turned on by them. But when gender does come into play I will admit that I'm attracted to men because they're men and women because they're women. I am also very picky I'm a lot more picky with women than men as weird as that sounds.
I've also noticed that I can be fluid in my attractions. I want men, women, both at the same time, or even people who don't identify as "man" or "woman". I'll have dreams/fantasies about men, women, and I recenly had a lucid dream that involved both a man and a woman. Or sometimes in my dreams/fantasies I am having sex with a person of one gender and the person of the other gender is there watching or actively involved. I get sexually and romantically attracted to both men and women sometimes at the same time, or I'll go through periods where I'm REALLY into one gender and I have almost no interest at all in the other one. But when I go through periods where I crave one over the other it doesn't make me heterosexual or gay even if in the past I'd wonder if I was when that would happen.