I'm setting up a new Sendero II in 300RUM for elk. I am new to the long range game and am looking for advice. For elk, what scope would you recommend? I have a vari X III, 4.5x-14x-50mm with paralex adjustment on the bell that I am considering putting on (currently on another rifle that hasn't seen use in a while). If so, what adjustment knobs would you recommend from the Leupold custom shop? (standard adjustment now). Will this scope give me enough adjustment on this rifle? I would like to shoot as far as possible, but only experience and practice will dictate my maximum range. I am hoping for 500-600yds. Are there any advantages to the Mark 4 series? I have heard that nightforce are top shelf. Are there significant advantages over my vari X III for my intended uses to justify the upgrade? Your experience and recommendations are appreciated.