While Civ6 still sucks (AI), I've been trying some non-standard openings with Civ V, avoiding either full Liberty or Tradition openers, and/or ignoring the standard early National College as well. One of those wonky strategies ended up being pretty powerful, mixing Liberty opening (Colective Rule + Citizenship), followed by Patronage (till Scholasticism). Liberty strong early game means extra cities with more rosources to sell. I also add some extra archers for barb quests. Patronage opener + Philanthropy makes CS bribes really efficient, and whenever I have excess happiness, I will sell ALL luxuries, INCLUDING last copies. National College only gives 6 science + 0.75 per population in the capital. If Liberty is done right, your capital should be somewhat small (8 to 10) in the Middle ages. So, instead of sacrificing a lot of hammers on that, I try some wonders instead. Petra sometimes is possible, but too much of a gamble. But Machu Picchu, is damn easy. Very few AIs take the Crossbow path, you can easily hard build it by turn 95ish by caravan feeding a city with a bunch (4~5) of mines around it, and beelining Guilds after getting all Ancient era techs. (Opinion: For ANY Liberty strategy, I think you should be going for XBs anyway, to get some extra cities, always! It is not efficient to self found them all) I don't think National College is required at all. Science may get a bit slow in the early Medieval, but when Scholasticism kicks in, things turn around. I can get a third of my science from it. Liberty finisher engineer is better used in something crazier, like Forbidden Palace, LToP. If not possible, I use it to get a scientist instead. I didn't find it too hard to get 6~8 CSs aliances by Renaissance, and ALL by Industrial (even against Alex). After that, any VC is pretty easy.