12 tracks is nothing! You don't need to worry so much about h/d performance if that's all you are looking for.
about the fat32 4k clusters. While you will certainly use a lot of tracks with this setup, 32k clusters will produce less hard drive stress on multiple tracks. i wouldn't argue it's essential that convert to 32k clusters but it's certainly beneficial long term and your drive will defragment faster (larger cluster sizes defragment quicker). it will also waste less disk space for larger files.