I don't think that the variables you mentioned can access the Windows resolution settings / 3D video card driver(s).

To access the Windows/3D Card Configuration you will need to use an A5 SDK to access the Win32 API functions and gather the resolution and color depth from Windows at which resolution/color depth you're on.. Then, you can compile the code as an A5 DLL (be sure you link your A5 header, C++, and library files (lib) if 3DGS SDK comes with a lib file but I don't have an SDK)) and in C-Script, you create a DLL handle, open your newly created DLL, and call the function to get the resolution/color depth information from Windows.

I have little or no knowledge of C++ so I can't help you out with it but I hope this helps anyway. I only have experience with C# which is part of .net Framework but just to let you know (probably as a reminder), SDK doesn't support C#.