Weighted side bends can build enough muscle to actually thicken the sides of your waist, rather than make it smaller. Remember, working with resistance will build muscle and most women aren't looking to build a lot of muscle in their midsections.
And here's a thread talking about the merits of the abductor and adductor machines that might answer your question: Hip abductors and adductors...what are they good for?
Good for you for doing a variety of exercises!
It's just that the ones above may not be the best for helping you reach your goals.