How long does it currently take to get through Seville customs and get a taxi to the Santa Justa train Station? I'm leaving in a few days and trying to figure out which train time to aim for (and hoping I haven't delayed too long for a train ticket).
Since you cannot predict if your flight will be delayed or not, my suggestion would be that you buy your ticket the same same day you land. I don’t think that the trains to Cordova get book completely so you probably have a good chance of buying tickets that same day. Hopefully somebody with more experience on that route will let you know if what I said was right or not.