Mika Yoga Wear sizing?

Hi, I want to order Mika bottoms but I'm a little confused about the sizing. I wear Small in Bad Kitty and Cleo the Hurricane. Small is my usual size in clothing, not only pole, but in general. I think I should order S/M in Mika, but I'm never Medium, so I'm concerned they may be too big in the waist. Or maybe should I order XS/S? But I have wide hips, so maybe this will be too small? I appreciate your advice. Thanks!