As close to the barrel as feasible is always the best option with rings. The Leupold website does not list the Omega but on a Black Diamond they suggest low for the VXII 3x9x40. I would take the gun to a shop in your area and find if lows or med will work best.

IMO/E you are better to forget see-thru's they are weak and suspect to POI shifts. Yes bearklr, I have used them so am not just preaching about what I do not know