First post from 1st time builder. Am building a .50 cal Isaac Haines style, Dunlap full curl maple stock and basic parts kit, with a Rice 38 inch B weight swamped barrel,rifled for round ball. Got everything inlet (wow- what an incredibly fiddly process!) and will soon need to mount the sights, which appear to be a standard set -blade front and a rear that has a flat top with a small center notch. My understanding is that the front sight should straddle a line 1.5 inches back from the muzzle and the rear sight should straddle a line on the breech end where the barrel thickness (top flat to bottom flat) exactly matches the barrel thickness at the front sight line. Is this correct? A quick and dirty ruler measurement (I'll use calipers when doing it for real) places the rear sight about 8 inches forward of the breech. I ask because most pics I've seen appear to show it more forward than that. This will be primarily a target shooting range gun. Wisdom and guidance gratefully solicited...