It is in my experience that using sizing charts doesn’t always work well. They are a guide and should be used as a size chart guide. When purchasing dance wear or fitness wear you should consider the sizing charts but think about how you fit into what you already have.
I have bought and worn a few different brands of dance tights. I find that I do not fit into the tights that they recommend for my height and sizing weight. I always go with tights a size bigger than the sizing charts suggest. I find that they are they are more comfortable. If there is elastic around the waist, it is not as binding and gives you a smoother line. I do not find that the next bigger size tights sag in the crotch or that they pool (make wrinkles) at the ankle. All I find is that they are more comfortable.
Dance leotards are all made a little different. Trying on a few at a brick and mortar store and buying them on line is very common. You get a feel for how to buy them so they fit great. Buying them on line can save money and the leotard you buy on line has never been tried on or worn by anyone. You get a brand new leotard.
When it comes to tops and bottoms, buying on line is a little easier. The sizing charts for tops and bottoms are fairly trust worthy. Also, you know from that rest of your wardrobe what fits you the best. Most of the sizes for dance and fitness tops and bottoms comes in the small, medium, large and sometimes extra large varieties. Buy what you normally buy and you should be happy.
Dance shoes sizing charts are pretty good. I have had good luck ordering from the sizing charts and getting what I need. I do recommend that you size your first pair of point shoes in person and then as you need to replace them you can purchase on line the same brand with the same size.