OK let's see here.
I'm not sure completely what you mean by "sexually open vs average". From what you are asking after that, what I assume you mean is "If you find a girl who has a lot of sex does it mean she enjoys it more? Are women who have lots of partners and lots of sex women who enjoy it?"
If that is the question, then no actually. It tends to be the opposite. Women who are very sexually promiscuous tend to use sex as a tool. They strongly believe that sex can get them what they want. And most times, it does. Also, unlike men, when a woman becomes sexually promiscuous, she tends to resent sex and a man's sexual advances because she sees herself only as a sex object. She may have made herself that way but she begins to hate that others see her that way. Most of these women will be very sexually aggressive at the beginning but their "desire" will die out when they feel they have the man. They truly do not have a love for sex.
That isn't true of a woman who masturbates. She doesn't always develop negative feelings toward sex. Masturbation is actually a great thing for a woman because it teaches her to listen to her body. She is more able to understand what excites her and what she likes. Which then means she is able to tell a man what she likes. But the thing about masturbation is that she may feel very comfortable pleasuring herself but very uncomfortable with a man in the room. So just because a woman masturbates, it doesn't mean she is going to be wanting sex 1000 times a day.
And to your last question, yes, women do have different sex drives the way men do. There are men who want sex 4 times a day and some who want it 4 times a week. There are women who want sex 4 times a day and women who want it 4 times a year.
What you are looking for, if you are looking for a woman who will always have sex with you, isn't a sexual woman but a sensual one. Some women like the sensation of sex and they tend to be the ones who want it more often. The problem with this is they don't wear signs on their heads. I know women who dress very revealing and masturbate everyday but feel weird about having sex with their boyfriends. And I know women who dress modesty and can't get enough sex.
You really need to look at the individual person. If I had a sign to tell you what they looked like I would tell you. One thing that usually is true of them, they tend to be older. Late 20's and above. Younger women do not appreciate sex as much as older women do.