With any flintlock, , you don't want to compact the powder for best accuracy. So, tilting the barrel to the side- as you must do to load the long barreled guns---- is advantageous, in that it allows the powder to SLIDE down the side of the bore to the breech, rather than DROP down as would happen when the barrel is held vertically.
Any barrel held vertically becomes a DROP TUBE no different than what BP cartridge shooters use in compacting 3Fg powder in their straight wall brass casings. Powder dropped down a barrel will Compact.
Done in a barrel with percussion ignition, you get good, consistent velocities, as the cap blows a flame right through the center of the compacted powder charge. But, in flintlocks, the sparks have to create heat that ignites powder granules from the back to the front, like a fuse, and compacting the powder has been shown to delay ignition of the full powder charge.
As to body height, or length of arms, they have some influence on how long a gun you will handle well, but balance and total weight of a gun and its barrel are much more important to how a gun "feels" to the shooter. Balance is how the gun feels when its held naturally in both hands, with the hands located on the stock in their normal shooting position: One hand on the wrist of the stock close enough for the index finger to be in contact with the trigger; the second hand on the forestock. Guns intended to be swung at moving targets- rabbits and flying birds-- then to have the balance in the middle, or just forward of the middle to give some steadiness to the front sight. Guns intended to be aimed- turkey and deer guns, or guns used to shoot sitting birds-- tend to use longer barrels with the balance closer to the forward hand, or beyond it. Moving the balance point forward steadies the front sight for an aimed shot.
Guns are tools, after all. If they don't work for you, you will find yourself picking up another tool to do the work. :hmm: :thumbsup:
I have known short statured men who own seriously long barreled guns, and are very happy with them. But, they use either a walking stick, or a handy tree for a rest for the barrel when they take an aimed shot, and have no intention of taking shots at moving targets. :hatsoff: