I usually go CR1,2,3, barrage for city attacking seige.
Barrage 1,2,3, drill1, shock for seige use out of city.
Spain, Cyrus (CHA/IMP), and other CHA or IMP leaders who fought alot to earn the GGs and are using Theo/Vass civics to have highly promoted units, can easily these. Especially, with Great Wall. Also, when you have cannons, and have out teched the AIs.
Boudica and Genghis are good at this too.