I'm 5'8" and I ski the 169's. I could ski a 179 bent, but it wouldn't be very mobile on jumps and what not. If you're a girl and you're 5'3", I would definitely not step on a pair of 179's, because you won't be happy.
Also, a 179 actually measures to 184, the 169 is 174 and the 189 is actually 194. They're called a 179 because they ski like a 179...but they're actually 184.
I don't mean to bust up your sale here bud, but you're giving people poor advice just because you want them to buy your skis...and that's not really cool.