Use a set of calipers and measure the distance from the top of your rear sight to the top of your slide at the 200 yd setting . Measure the same for the 300 yard setting . Doesn't matter exactly where you measure from as long as it is the same both times and repeatable , it's the difference between them we're after . The difference is how far the sights move to get the changes you see on the target for that rifle . From that you can break the ratio down to an amount of movement per thousandth change . This change will occur no matter which sight is altered . The only difference is the direction of movement is reversed . Ie , raising the rear sight raises the grouping , lowering the front sight by the same amount amount will have the same effect on the target .
HTH , Chris