concrete numbers are completely worthless with our current knowledge.
you could as well answer the quesion of "how much damage should missiles do?" with "5".
its as worthless because it exists in a vacuum, without any other numbers to give it any meaning in the context of the game.
what dino said, basically.
give practical constraints which are independent of the actual numerical parameters in the game.
"1500 meter" means nothing without the rest of the game "fighter dogfighting range" has meaning because we can imagine the distance in a gameplay context, regardless of the actual numericals that they end up being.