basically, the screws "deform" the coldplate to make it match the CPU IHS. The CPU is never perfectly flat, so the screws are here so you can bow the cold plate to make it fit as closely against the CPU as possible.
typically an IHS is somewhere between flat and slightly concave. the Vario allows you to make the coldplate convex.
The setting will vary from CPU to CPU, there's not two identical so you'll have to experiment.
I also bought a cuplex kryos vario cpu block with a silver baseboard
After completing the assembly of the ancestor, start the test
I read a few online reviews of vario features
Whether it is extreamrig or techpowerup
The most impressive thing is a sentence
"Most people can't set vario correctly"
So this is a challenge