Gone through the misery myself - open sights are the most subjective things there is on a single rifle - IMO front bead/post is all about opposition - accuracy/speed, however the rear has nothing to do with speed - it is all thoroughbred accuracy - IMO make the bead follow some possible divisions according to position of the bead vs rear - I guess you will have to go throught this yourself - i.e. make the "V" as shallow that bead will seat on the bottom with "ears" coincise with top of the bead and call it a close call - up more - the the middle of the bead will coincise with top of the "ears" makes it a middle range and bottom of the front bead coincise with top of the "ears" make it a "long" range - whatever that means (and all in between) try it yourself...IMO - with 2mm bead in praxis 1/2 bead (1 mm) difference on the end of my 9,3x74R 23.6" Merkel bore/vs rear, means ~ 3" on 100m according to my observation...