The only reliable LKP available to the public is the last SSR position.
Note that it's a few degrees above the equator.
Moving West from the LKP would reduce the distance to IOR -- as would a course of 180 True until crossing the Equator, whereupon the distance would steadily increase.
The first ping arc after LKP coupled with a/c g/s might be useful to determine whether MH370 turned North or South. The second ping arc may also be helpful in determining the relative probability of which way the a/c turned.
That said, there remains the possibility the a/c assumed a closed course. In that case, we might see a steady oscillation in ping arc distances or a constant one depending on cycle times. For example if the a/c was tracking a wide circle n times an hour, the ping distance could remain constant.