Virgil, This will get you close:
For example:
Distance to target = 100 yds
Point of Impact = 15" higher than Point of Aim
Length from rear sight to front sight = 24"
Height to ADD to front sight = 24" times 15" divided by 100yds (ie 100 times 36in/yd)
= 24*15/100/36 = 0.10" (or just under 1/8")
Just substitute your numbers.
