SRP: Setting filesystem permissions -- "Authenticated Users"

I am trying to set up SRP+LUA on a win 7 pro system.
There is an "authenticated users" group which has write permisions on C:
The "write allow" box is greyed out, I can only select "write deny".~But then I get the warning that deny will take precedence over allow, and I´m afraid that admins will get denied if I check the deny option.

How should I set this properly?

 

My authenticated users on c: allows any modifications, nothing is grayed out. Hmm.

Sul.

 

My bad, I was looking at a subdolder "swsetup" which is where the drivers were being put in. The parent C: directory allows all modifications, the subfolder was probably inheriting the attributes.