Best climb depends on current mass. Being heavy speed a bit higher than when a bit lighter. And the speed decreases with altitude (but depending on what chargers are used).
Best climb rate (feet/min up) is not the same as best climb angle, which is reached at slightly slower speed.
Gliding for maximum distance isn't at best rate either, but at slightly higher speed.
The proper numbers are documented in the respective planes pilot operations handbook.
In the game I like to set the speed much higher. Getting anywhere faster is more important than getting higher (usually).