Here is the deal, I am getting a Leica 1600B and want to know how advanced of a Kestrel do I need if my shots will be no more than 500 yards now & maybe 700 yards in the future/ I hunt in WI, MO, OK and KS and the elevation varies from 700-1100 ft depending on the state. I would like to keep it simple as possible for the time being. How much will pressure figure into my calculations? I shoot a 30-378, 7mm STW & a 7RUM with with either a Leupold VX-7 or Nightforce AtacR. Also which iPhone app is everyone using? I have the Ballistic AE app now.