Remember you eye prescription is different than everyone else. The numbers are not always going to line up with the numbers on the parallax.

Any Arken scope will work, just a matter of what features you want. For a frame of reference, 10x will get you out to 1000m. A tip on the savage, I have the same one. Remount the scope base due to savage does not locktite the screws or base. It will come loose.

When you do a boresight on it , you will adjust it to where it needs to start

That's the spring plug adjustment that opposes the Elevation and windage axisis. It's a 3 piece design as opposed to the German 5 piece. Don't try and adjust or remove it.