If there is any accuracy to the notion that preplanned duels with pistols was a real thing in the old west, which I assume there is considering pistol and sword duels were a thing on the east coast and Europe at the time and prior. Did they really arrange to have the duel at noon? Was this so both parties could be sure to KNOW when the fight was without error? Is it possible that it was made to be noon because then the sun would be overhead and neither shooter would have a glare disadvantage?
Hate to rip out the rug from a fellow Old West fan, but there really isn't much truth at all to the concept of "Duel at high-noon" (Or at least not to the degree that we we want!) . I can't speak for other time-periods though. Your stated reasons are probably why that became the common trope though. The few duels I've heard about were not really pre-planned, more spur of the moment, "Let's settle this with lead since there aren't any cops around!".
I'll leave you with this so you have some faith in the Old West: Kit Carson was one of the quintessential frontier-men who truly did pull off some crazy stuff. At one point he became so fed up with a fellow mountain-man of French nationality that they settled it right there. He won the duel, but received a scar on his face. The hot powder grazed him! Blood and Thunder is a pretty interesting book, if you like this kind of thing.