My best kill ratio is about 25-33% with Snakes, usually it's around the historical 15%. I generally get my best shots a little below the target, where the seeker can see blue sky all around it, so I'll oft times head for the weeds in pursuit, and use a Russian style uppercut technique, especially in the Crusader. Last night, flying the new Mirage Factory F-8E, I fired three Sidewinders at a 17 from beneath his tail with a good loud tone on each missile, no manuvering from him because he didn't know I was there, and only the last one got Mig parts, while the Mig driver was apparently wondering where those two smoke trails were coming from. Then again, I've had a number of missions where I've been so target fixed that I didn't notice the smoke trail of the Atoll that should have killed me until I flew through it, so I guess the AI's behavior in this case probably wasn't that inaccurate!
Heck