These tights are the perfect material for what I was looking for (thicker cotton, not nylon-like, but not heavy either).  HOWEVER, they are VERY slender cut.  The length is perfect for my daughter, but they are hard to get up her leg and over her tush.  She's in the 99% for height and 50% for weight, so that shouldn't be a problem.  Once up, they stay put and don't seem to be to tight, but getting them on is quite the task.