I wouldn't really call Tonberry a system, more like a texture replacer.
You download Tonberry, put the files and folders in your FF8 directory, and put hashmaps, objmaps, and textures in the respective folders.
Unfortunately, one of the main modders for this, Mcindus, has had his downloads removed due to the domain going down, but there should be some mirrors, and he is trying to get the files back up.