I have some solution, which worked for me.
Before the first launch you have to clean up at least 16GB on disk C: The game trying to write the config parameters and set rolling cache file in default location in APPDATA.
So, let the game write the config and set cache file, and after that you can change this parameters.
You can find the changes after next game launch in rolling cache section, cache size will be 16GB.
No guarantee, guys. Just works for me, MB will work for you.