If you can, I'd grab a copy of "Making It All Work" - it's a great resource for those upper levels, and even includes recommended frequency of review at each horizon, as well as what the "output" at each level might look like (i.e. straight list, mindmap, etc.)

I've found it really depends on what you've going on at each horizon. For instance, I used to have a mind map (in MindManager) for all my Areas of Focus, and now I've got a hand-drawn mind map and affirmations for each area in my paper planner.