The field card from the dead on ballistics software will tell you where to hold for different distances and magnifications. using the field card, it doesn't matter what magnification you use. I'm sill practicing but it seems pretty accurate so far.
There's an app for that.....I down loaded an app for my iphone its called Nikon spot on its pretty accurate so far I have used it to compensandate for different grain bullets in my .243 you first select your scope, caliber and ammo, then set your zero, tap the fire button and it brings up your BDC recticle and shows the yardage for each circle and you then can change your magnification and it changes the yardage accordingly.
I have found the reticle works well at 11X - this gives me hold over points for approximately 300, 400, 500, 600, and 700 yard shots. These are approximate and adjusting the magnification will change the yardage for point of impact on each reticle circle.
You really have to go out and do some variable distance shooting and characterize the magniification settings for your particular rifle and ammo.
I am confortable with shooting mine out to 700 yards after a couple of hunting seasons because I have done enough shooting with it at different yardages to have some confidence.
I highly recommend the Nikon BDC - it works well and I am looking forward to doing more long range shooting with it.
You can download the Nikon app on your phone "Nikon Spot On" you can select your exact Nikon scope, caliber and exact bullet and it'll show you everything you're asking about. Or you can go to Nikonspoton.com
I have learned quite a bit over the past few years turkey hunting and the majority of it was how to get that tom within range. Every article you read is littered with talk of fighting purrs, flydown cackles and clucks. What they don't tell you is now that you've caught that tom's interest and he's coming on a string... now what? I have seen more blown or missed turkeys from lack of experience in this area than I can imagine. If you can't seal the deal than you may as well have left the...