If you use the Italians as a role model, this is what my old boss, Lenny Preheim (RIP) observed. They consistently set up handlebars the very same way.

Top of bars slopes downward slightly. Bottom of bars points to rear axle or slightly higher. I.e. neither drop nor top is horizontal. Tips of brake levers protrudes very slightly from the plane formed by the extension of the bottom of the bars. I.e. you can run a ruler along the bottom of the bar, and the tips of the levers intercept this ruler.

This positioning makes the levers accessibly equally from the top and bottom.