Two things to add here. First up, the Library folders can be moved out of the C drive and I think it best that you do this, keep the C drive for programs only if you can. The kit and beat files load time remains the same, too. I’m saying, if you haven’t done this already, the entire Cubase ‘VST Sounds’ file can be moved off the C drive. I install my added GA5 Kits here, in this same file of course - ‘VST Sounds’ - which is where Steinberg installs the original kits, as well, along with Halion sound banks and the various synth sound files. All that you have to do is DIRECT THE LIBRARY TO THE NEW LOCATION, and this is easily done, (see Library ‘Settings’, upper right hand corner of the Library app).
OK, second thing. Like you, I questioned where all this 30G of information is accessed in GA5. What I found is that you can access it in a second layer of GA5. Here’s how:
Load a Kit in GA5. Next click on PATTERN. Looking now under the Kit, you see the orange colored AGENT button and the field below it showing the circular STYLE controller (with Complexity off to it’s right). Next to the Agent button, you’ll see the grayed out OVERVIEW button. Click on it. Now you’ll see a drop down of 16 items that mimic the GA5 keypad for the kit you’ve loaded. Click on say the orange MAIN 5 of the pads, light it up. Now see the orange surround move in the overview dropdown display to follow the pad choice. OK, move you mouse to this new window (under the drum kit) and move the mouse to the far right side of it. Click in this area. You will see a drop down icon appear, click on it. Now you will see all the beats that are stored in your library. You can choose any one of these, Blues, Reggae, Songwriter, etc., and - although the beats may not match your original Kit style, you can click on it and it will be incorporated into your original kit, all in sync with your potential drum program, and now all controlled by the 16 pads.
Now, if you knew that GA could do this, then this probably was a boring read. But, if you didn’t know the program could do this, then I think it could explain where all the Gigs of sound files can be accessed and also explain how to use it creatively. All the best.