The finished-after-sighting sight height depends not only on how high the sights are, but the load, calibre thus velocity to some extent and the way you see the sights as
well as how you hold the rifle, or smoothbore.
Mathematics can get you close, but oft times, the height of the front sight starting exactly the same as the rear sight, will give you room for correction. If you want a zero
further out, then the front will of necessity be lower than the rear, again, dependent on the load. I have had rifles/barrels with front and rear sights the exact same height.
I just checked the sights on my .36. As you can see by the target posted for Nov., it appears fairly zero'd at 50 yards. Offhand, it is, but shot the way I did this target, it is
shooting about 2" high at 50yards, not holding onto the forend and resting the back of my hand on the bags. If I do that, it is zero'd at 25 & 50yards.
The .36's front sight height is .172" above the flat. The rear sight is .251" above the top flat. The barrel is 13/16" straight. Distance between the sights is: 27"
My .50 Beck is shooting a wee bit high at 50yards from a rest, without holding onto the forend, but is zero'd if I do that. The .50 target I posted, shows it is shooting 3" high
at 50yards, shot to let the forend move as it will, on the bags.
The front sight height is .566" above the centre of the bore. The rear sight is .600" above the centre of the bore. This is a swamped barrel, thus the bore centre measuring.
The distance between the sights is: 29"