Paul, I ask your indulgence in my commenting on your posting as noted above. I believe your statement in general terms, by 1800 all of Europes artillery was made virtually the same way, and operated the same way
is correct and I would further add, were fought with equal efficiency..
I submit from the Napoleonic period, if you picked a class of guns or a weight of shot.. 9 pdr - 12 pdr to make it as equal across the board as possible, (considering the uniqueness of every individual piece) the best representative gunnery crews from all the participating nations, using say 4 guns batteries per nation, the guns they know intimately, service and love as only a gunner can appreciate (and the professionals knows that each gun barrel has its own anonalies as in the smooth bore musket of the time having various windage and trigger lock time) with the powder and shot being supplied by neutral party. and run the competition over 3 to 5 days where they have to move the guns, carriage and uncarriage the guns .. all the normal sequencing that is done, you will have a result with some reasonably empirical data to analyze.
The old time Napoleonic gunner, irrespective of country is a connessieur of range and wind as much as the current military specialist sniper teams. I submit that after 3 to 5 days the point spread may well be in single digits. I have seen this in modern day multi-natioinal military/police competitions using their issued weapons, all educated and trained similarly but with unique applications in some cases, with some nationalistic styles and systems from both sides of the old iron curtain. When on the firing line, it is the precision fire on target that is the only determiner of success.. The shooter and spotter behind the precision rifle or the gunner and gun layer behind the artillery piece of old were the catalyst - regardless of ethnicity or education or rank..