16 clicks is the correct number, 8 would move it 1/2" at 25 and 1" 50 yards.

Now not all scopes track true, so you may find it more or less depending on how the scope tracks. But as it states on the scope this is how much you are supposely required to move it 1" at 25 = 16 clicks. (which equals 4" at 100 in theory) It will get you close to where you want it to be, then fine tune it 100 yards.