Although the two flights may be scheduled to arrive within 15 minutes of each other you cannot tell which flight will arrive first especially when a longhaul flight is involved. There can be a long walk to passport control and depending on the time of day queues could be considerable especially in April.

I agree with MSPeconomist that meeting at the information desk (no.6 on the map) after customs would be best. Free airport wifi should work especially once you leave the passport control/baggage claims area.