Set your scope on optical center. You can do so by turning the turrets all the way in, then turn all the way out counting clicks or number of turns. Now go back half way. You can also use a mirror against the objective lense. With it it centered, you should be near center of target both windage and elevation wise requiring only a few clicks to get you on center at 25 yards. If your POI is far from your POA, you may have slight issues that can be corrected. Keep in mind that your fixed 4x likely has a different parallax setting than your variable
But the again, you could be canted.......never mind, lol.