That's a huge amount of elevation for only 430 yards. I agree with others who suggest the target is above the bench necessitating the shooter to aim up.
For comparison, below is a picture of a friend shooting at 800 yards with an Enfield at Bisley (Surrey, England). The range here is pretty flat.
The Muzzle Loaders Association of Great Britain holds national rifle championships matches for the Enfield out to 600 yards. A club I belong to has an aggregate match for the Enfield of 15 shoots at each distance, 600 & 800 yards.
For 800 yards it varies with shooter, but average will be 80-90 grains of an FFg equivalent (although some use more). Some have modified base plugs for their Minie bullets such that they cast with thick skirts.
The hardest part of the recoil is having minimal contact of the head on the stock. It can leave the head unsupported giving a sort of whip-lash effect. The straight stock of the Enfield helps here when compared to other contemporary rifles shooting the Minie bullet.