The strength of your position is starting to show up in this round. By the end of next round it should be a runaway.
I agree that Astronomy doesn't look as valuable as a Liberalism tech at the moment. Nationalism definitely has a nice upside. In addition to Taj Mahal it gives you the ability to build Hermitage in KS. It gives you the pre-req for Constitution (which gives you Representation to add to the Caste system/Pacifism civic combo) and would let you consider a bee-line to Democracy (although that will leave you vulnerable in military techs unless you can make some trades).
One option that you didn't mention is to trade PP to Huayna for Banking now and then take RP as your free tech. That would mean you would only be two techs away from being able to field rifles. I think Nationalism has more to offer at the moment but if you're really concerned about an attack from Mehmed RP may be best choice.
Another way to deal with the copper is to generate a Great Artist and culture bomb Ning-hsia. That should give you control of the copper tile and will probably flip Izmir if it continues to be totally lacking in culture. (Another one of the AI's moves).
I agree that Astronomy doesn't look as valuable as a Liberalism tech at the moment. Nationalism definitely has a nice upside. In addition to Taj Mahal it gives you the ability to build Hermitage in KS. It gives you the pre-req for Constitution (which gives you Representation to add to the Caste system/Pacifism civic combo) and would let you consider a bee-line to Democracy (although that will leave you vulnerable in military techs unless you can make some trades).
One option that you didn't mention is to trade PP to Huayna for Banking now and then take RP as your free tech. That would mean you would only be two techs away from being able to field rifles. I think Nationalism has more to offer at the moment but if you're really concerned about an attack from Mehmed RP may be best choice.
Another way to deal with the copper is to generate a Great Artist and culture bomb Ning-hsia. That should give you control of the copper tile and will probably flip Izmir if it continues to be totally lacking in culture. (Another one of the AI's moves).