I haven't done the Cholas UHVs (I think that's the conquest one) but the culture one (Cheras) wasn't too hard. I captured all the cities in Tamil Nadu through culture flipping by 220 AD, then just spammed farms everywhere. The Cheras capital gets crazy production so it can churn out temples and pilgrims really fast. In the other two cities I just had all farms and then 2-3 labourers. The Mauryas were nice and gave me Buddhist Wisdom for free and I built a missionary in the city in Kerala, otherwise it was just a lot of culture and building pilgrims.