The question is sort of like... "I am building a quick fast sports car for Autocross and slolem, but I have these fantastic 40" tall Mudder tires that I want to use - Love em. How do I get all of this to fit together?
The rifle you are describing is really sounding like more of a sniping type set up with the verticle type grip etc.
Use the Nightforce on a beanfield or Varmint rifle and get some compnents that all fit together well is my advice. A Loopy or Burris 3.5-10 or 4.5-14 x 40 is all that is needed for a lightweight 300WinMag.