JMHO - I would not burn the Liberty GP that way. When I finish Liberty, I always take a GS if I'm behind in tech or a GE if my science is strong. In the latter case, I use it to build some wonder (e.g. Petra) that would be risky to hard build because there's always the chance an AI will beat me to it. With the NC and other national wonders, there's no such risk so hard building is a safe option. Look at it another way -- you could choose a GE or a GS for the Liberty finisher. If you choose a GS for an academy, you get an immediate +8 and it lasts for the rest of the game. If you choose a GE to rush NC, you get the NC benefits 10-20 turns earlier (+3/+50% , +1 ), but no academy. I'll take the former every time. Happy conquering!