I have a VX3 3.5-10x40mm Leupy that I am ready to order CDS turrets for my 7 Rem Mag. 168 berger and 100 sierra. I live in Illinois. I need the turrets calibrated for where I will be hunting @ 6000-8000 feet. What will guarantee me the correct calibration of said turrets with velocity info from 550 foot elevation here in IL? Thanks in Advance!