Survival skill FINDs terrain for Ambush; Tactics skill to best utilize it?

[Rupert]

I think Tactics would be the primary skill - to set up an ambush you need to choose your spot, and lay out your forces, etc., and this is all one skill.

However, a complimentary skill could be Area Knowledge (which their local allies can provide) or Naturalist, which I think tends to be under-utilised and over-looked by many players.

There is a real-life name for a skill that'd let you locate a good ambush spot and set yourself up, but not necessarily actually execute a good ambush - Fieldcraft, but there's no one skill in GURPS that covers this, and it's one of those skills that's a little different depending on what your overall 'profession' is.