25% is about right for indian gdp around mughal period. http://www.ritholtz.com/blog/2010/08/history-of-world-gdp/

these early wins were against muslim rulers who did not have that much support of their majority populace because of taxation issues and also suffered from lost revenues due to the new trade routes.

the hardest wars were against the hindu/sikh rulers - marattas, rajputs and sikhs who were not subdued until 1850s with great effort.