For size reference I would try to stay within 1 MOA gong at specific distances to keep it a challenge. I would get larger gongs for fun. So like your 5 inch plate is for 500 yards. Or you can buy a big gong spray paint a specific size circle and aim for that. Misses outside of it can be used for sighters to make W/E adjustments.
Here’s a thought. Could you place a piece of metal or something behind a swinging gong so when you hit it, it swings and strikes the metal bar behind it to give a louder sound??
EDIT: it would help if I read other forum members post. I just said exactly what was previously mentioned.

Here’s a thought. Could you place a piece of metal or something behind a swinging gong so when you hit it, it swings and strikes the metal bar behind it to give a louder sound??
EDIT: it would help if I read other forum members post. I just said exactly what was previously mentioned.

