Your pay package will be significantly higher if you go as an expat, rather than as a local. The OCI is not "dual citizenship." It is similar to the "green card" in the USA, giving you certain privileges based on Indian heritage. Besides as long as you go as an expat, you don't need to convert your licenses. The only advantage to going the "local" route if you hold a foreign passport is if you are low time or don't have the PIC time the airline is seeking. India does not hire expat F/O's, the last I heard.