The B0XX default layout is objectively the most ergonomic and you should use it if you're serious about competitive Melee; however if you're a beginner box player or are otherwise having trouble with how it feels to play on a flat controller, I think this custom layout could be a great place to start getting comfortable with the buttons.
The purpose...
"Simple" B0XX Project - B0XX button mapping for beginners
Source: https://smashboards.com/threads/simple- ... rs.520650/