I have a Cooper Model 21 montana varminter 20Tac. on order. I want to put a Nightforce NXS 8-32X56 with NP-R1 reticle on it. What height rings will I need? Also any recommendations as to brand/type will be much appreciated. I have the same question e-mailed into Nightforce and Cooper but have not recieved an answer. I will call them if no avail, however, if any of you fellas have suggestion.......much appreciated! Oh yeah...I'm using it for Praire Dogs.