On a different note: is there a G&K culture preimer some where? For some reason when I've tried past gauntlets I end up terribly behind.
It's not written. I've seen people argue for 1 city, 2, 3, 4, and occasionally more. Most seem to favor Tradition, Piety, Freedom, and Liberty if going with 2+ cities, but there isn't consensus on whether to take Patronage, Commerce, or Honor as the fifth. Occasionally someone wanders through and suggests that Rationalism trumps piety for unlocking culture buildings and wonders faster, and on higher difficulties, they might even be right. The occasional madman wants a very wide culture game.
The most common answer seems to involve 2-5 cities, complete Tradition first, Liberty down to reduced policy costs, Tradition down to reduced policy costs, and then completing Freedom as the second complete tree. The second most common answer seems to involve one city and skipping Liberty. Great artist production is probably the most important argument for more than one city, however, with science, gold, terrain-based wonders, and local culture production that pays the marginal cost being the other reasons.
I do wonder if completing Tradition before Freedom is really optimal. Faster growth is good, but is it good enough? Perhaps with a game where you are strong enough on other merits to get to Industrial quickly without a complete Tradition -- Aristocracy, Legalism, and Monarchy obviously rock -- you'd also get a faster time because you'd finish Freedom sooner (before going back to fill in the rest).
Some strategies don't involve puppets, but could Sacred Path and a rainforest map change that?
Given the scaling on Large and Huge maps, they'd probably need their own strategies.