The Samsung manual said "SIM 1" should be your primary SIM. Feeling like a fool for not following through on all ramifications all this while.

Please if you're using a dual SIM phone always use the SIM with data plan subscription as SIM 1. Doing otherwise and using it as SIM 2 will probably not guarantee you the best of browsing speeds.

At this juncture I have to apologize and pay respect to Airtel. The network presently with the cheapest call rates and data plans. Data plans...BIS usable on all devices without need for any hack and presently with the benefit of a generous promo. Airtel ndewo nu!