O.K. I finally deceided and purchase my new rifle,a Winchester Model 70 Classic Featherweight in 7mm08

Now any input as to which of the 2 scopes I already own I should mount,Leupold VXII 3x9 target dot 40mm,or Leupold VXII 4x12 AO 40mm.Also can I get away with low rings or do I need medium?Forget to mention will be using rifle for range shooting and deer hunting,some woods as well as some large opened fields