Just use whatever sensitivity is most comfortable. I personally use about 30.5cm for a 360 turn (aka 12 inches/360 for the Americans
), which is the same that I used in Quake, Unreal 2004, TF2, Call of Duty and pretty much every FPS game I've ever played. It's a bit on the low side for KF - a game that requires tons of quick 180 degree turns - but I have a big mouse pad and can make it work. I find it better to stay consistant over constantly switching to different sensitivities. So fool around a bit with it and use what you personally like best. If there was an optimal sensitivity there would be no need to tweak it because every game/mouse driver would default to it.
Also unless you use high sensitivity (< 18cm/360) in FPS DPI is a marketing scam. Most mice actually work best at low sensitivities; when I play I set my MX518 to 400dpi and Deathadder to 450dpi. It's helpful for RTS games but for FPS it really means nothing. So feel free to use whatever you like, and just because your mouse goes to 6000 DPI doesn't mean you should feel obliged to play at that and that it will make your game better.
For binds/settings, I stay pretty much vanilla. I'm a big esdf supporter but KF, along with L4D, is pretty much the only FPS I use wasd.
Controls are pretty much default except I use F to drop weapon, mouse4 to throw grenades, and mouse5 for mumble/ventrilo with friends. Left shift is my microphone button but I hardly every talk in game.
For settings, low graphics never really made it much easier for me so I keep most settings on high except for the 'bad' effects that hurt gameplay, such as weather and motion blur.
Also it is very, very important to turn mouse acceleration off! Aim improves from repetition and practice and accel throws everything off.