For human reasons just about every detector operator feels they can improve on what Minelab have suggested with their factory settings. I would suggest start from there and practice on known targets to see what settings you can get away with.
As you would no doubt be aware, identifying a target signal when searching is a different beast to hearing a target when you know it’s there.
You will then need to identify two lots of settings. A less aggressive group for general searching (around default setting levels), and a more aggressive group of your own for intensely detecting known nugget producing ground. You can retain them in as custom settings.
Good luck it’s a great machine and make sure you have coils to suit. A large, medium and small. The latter (an 8” or 9”) is often overlooked in the 5000 armory but complements the 5000’s improved small gold performance over previous machines very well.