in regard to the tznuius thread, read the book “oz vhadar levusha.” Its a little machmir but you’ll get a clearer picture of why certain clothes should not be worn. I wear most types of clothes out there but as far as slits go, I see on my friends’ skirts when they wear slits on short skirts, guys get extremely attracted to it, probably when their upper leg keeps flashing through, and girls really need to be aware of what they are causing when they wear these skirts.
with cap sleeves, they are halachically tznius and thats mostly what you’ll find in department stores. I think it’s beautiful when you can instantly recognize a jewish girl when she makes sure to wear a long sleeved shell under something that is otherwise not tznuis