I rarely get farther than renaissance, so settling in a manner that properly exploits the third ring is rarely a consideration for me. I do play with the game option that allows third ring through culture, but there are many, many turns in the early game before cities naturally grow to that size, so I tend to stick with designing around the normal 2-ring fat cross. If I plan only to exploit a resource from the third ring, I won't have access to that resource (or the special bonuses of that resource, e.g. vicinity buildings) for a long time.
So I favour the "what can I do now" approach. If I ever get a game to the point that I could work the third ring on settling (or at least not needing to grow culture through however many tiers), I'd adjust my strategy, but I doubt it would change all that much. It seems very likely to me that any game running that long - unless it was started in an advanced era - would long ago be completely settled (I generally play on small or standard sizes to help reduce turn times).
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On a slightly related note, I kind of wish cities could have access to river and coastal buildings if those features are in their fat cross, not necessarily for having settled directly adjacent to river or coast. It is sometimes possible to have these features within range of a city, but because of strategic considerations (for example, having to choose between settling against a river versus settling against the coast), they are not immediately adjacent to the city, preventing access to many buildings. But, I suppose, that's just How It Should Be: after all, not every city can be perfectly placed.