5D premade fans - what can I tell you they suit to most people as it is a very very versatile fan size and it would not load natural lash too heavy.
If you are a beginner and are still learning which type of lash fans to get this is a very good choice as it is perfect for majority of the people as you will build your knowledge base by seeing lots of different types of natural lashes, their thickness and getting used to them.
This is your perfect option.
320 size boxes are little bit wider fans, leaving fluffier finish
480 size boxes are more thinner on the top and therefore create illusion of darker lash line.
