gwiz
Why would you only have a single shooter?
Why on earth would you have more than one, or at most a group firing from a single position? Three shooters from three different angles is a ridiculous way to try to persuade people that there was one shooter, as well as tripling the chances of being discovered by accident.
The trouble with the JFK conspiracy theories in general is that they assume a simulaneous complete control of every variable, and an inability to control anything. If you need three shooters because the odds are that one cannot successfully pull off a fatal shot, your solution should be to select a better vantage point (or shooter), not have people firing from random compass points. If the grassy knoll is a better location, put the shooter there - not also two other places. Heck, its relative concealment would allow the plotters to shoot and kill a "patsy" on the spot, instead of allowing Oswald to wander off the scene completely unnoticed.
The only reason why conspiracy theorists get obsessed about multiple shooters is that it allows them to stare at fuzzy polaroids and play "let's find the anomaly".