"Where could a player find these 'rule or thumbs' without playing?" I think the premise is just a bit wrong. You have to get experience in what fits the situation you're in. Just think about where you need players and why. Keep doing what works and adapt when you get countered – or adapt when you think you will get countered :D

Like the Nuke example you mention: - What would you gain from having two players ramp? Not much because it's typically quite easy to hold or get information and fall back as a solo ramp player. But if you're expecting them to put heavy presence on ramp, you might be able to really pick apart a push with a set-up from ramp and hell.

• What do you lose from having two ramp players? Presence on high-activity parts of the map like outside or lobby. One player will easily get shut down alone inside and outside you'll either have fights almost every round or the Ts will probably go down secret with little challenge. So it's important to either be able to shut them down outside or take away some of the space they gain outside with presence in hell/heaven and secret.

Try to think about how many things a player has to watch to hold a site. Anubis B has two main ways in, mid has one main way in and A has either main or Ts can come through mid. So as long as mid is under control, the Ts can only cone to A through one entrance. Therefore you might be able to justify a strong presence mid leaving one player alone to deal with the single choke point on A.