red numbers means you spin the prop in the noise region. Yanks like that, Europeans get banned for that.
To define the better prop, look at the thrust charts for engine 1 and engine 2. Often the small pitched prop will be better at taxi speeds, but as soon as airborne, higher pitches cut the cake.

Use the chart as a tool, not as an end in itself. 23x8@6500, juggle the numbers in engine 2 until you find comparable horsepower at 6500 rpm. This prevents you from getting overoptimistic dreams, and narrows down the choices of props you have.