Keep in mind that a lot of battles reward the player who lands the first shot, so sometimes a fast sensitivity that lets you snap to an enemy at close/mid range can pay off big. Accuracy is the most important but speed is a close second, else you might die before even getting the chance to fire off more than 1-2 shots.
Most good players I know can do a 360 with a horizontal movement between 3-10 inches (it depends in part if you're a player who moves your entire arm or just your wrist. I do wrist). I myself use a very high sensitivity and can do it with 3, I think most players average around 6 inches. Mouseaccel is very bad. Turn it off everywhere (windows, mouse drivers, in-game)
Scripts will not improve your game very much it's mostly a waste of time. I've tried using some in the past and ended up throwing them all out. It's more important to focus on consistency in your settings and simply to concentrate on the game. The only thing I have now is gear loadouts. But Cuomo since I know you like scripts here's one I thought of just now that you could try. I myself would not recommend using it though so lol.
set low "sensitivity 1"
set high "sensitivity 1.5"
set s1 "+attack; vstr low; ut_echo ^2LOW SENSITIVITY"
set s2 "-attack"
bind mouse1 "+vstr s1 s2"
bind g "vstr high; ut_echo ^1HIGH SENSITIVITY"