Do these sit at the natural waist? Is the fabric more like a double weave or a true denim? And is the fabric heavy, medium or light weight? Being labeled as slim-leg, do they fit close to the hips or do they run larger there and hence (due to elastic waist) fit with a belly bulge in the front? Finally, I wear a size 10 regular (tall if pants are short) and am on the tall/slim but not model-slim side, so should I order a 10 or a 12, seeing as so many reviews said they run small. Thanks for any or all answers.