I hunt froma treestand better than 95% of the time with a muzzleloader. It is very acceptable. I hang my gun on a hook with the barrel pointing upward, unless precipitation is falling. It is wise to check the load at the beggining of each hunt to se if it has moved. Make a mark on your rod after it is loaded. This will be a reference point in the future. If the load moves you can check it by the mark on your ramrod.

As far as the angle of shot from a treestand it all depends on the sharpness of the angle. There should not be much of a difference. Just remember that you want to hit a little higher if aiming at a steep downward angle. An inch or two higher will ensure that you get a double lung shot instead of a single lung shot, if you do your part.