I really like this hack so far however, you might want to nerf the Chapter 5 boss. He has 18 strength and 15 speed meaning he doubles or one shots almost everyone in your army.
You have to patch it to a rom before you can run it in a emulator. Get a clean FE8 rom and apply the download to the clean rom using this, https://www.romhacking.net/utilities/519/ . After that just plug it into your emulator.