When comparing the 20 Classic series, Set #2 is less incut and easiest on lower angled walls, whereas, Set #1 is more incut and easier on steep walls.
Set #2 has a variety of flat and rounded edges that you can edge and push off. When using this set on steeper walls, expect to be pushing hard into them to be able to stay. Core strength is required!
Many shapes are omnidirectional, which means you can rotate them for a less positive version.
This size of foothold is only appropriate to be used with commercial climbing shoes.