This is like asking a bar full of patrons which beer is the best. They are equaly skilled at getting lit with their favorite brand because thats what they drink most of the time.
I find some times depending on the map, with the P51D I have to move my convergence between 275-350 to increase my kill probability. Who knows....some maps have more going on in the background than others possibly eating up some of my processing. Or it's a bad night on the internet. On the nights that the first two Texas routers in my PingPlot are not acting up, anything I point at 400 and closer, then pull the trigger goes boom. When those routers or just one of them are acting up, many of the sight pictures where I pulled the trigger previously, the cons don't go boom. More likely I'll get assists and even have to adjust my convergence to improve my assists to late kill messages.
It's kind of hard not to notice these things after playing this game for 10 years.