How to access to System Files with Spotlight ?
Go to the menu File>New Smart Folder
Add a new condition with the + button.
In the Kind field, choose Other and select "System Files".
Now you can include all system files in your search queries !
How to add grouped conditions with All, Any or None ?
It's simple. Before to click on the add button, press the "alt" key on your keyboard.
The "+" becomes a "...".
Now you can play with all conditions...