Well, on the first question, I find it easier with a lower sensitivity than 10 (what I play on), but it definitely doesn't matter. Look inversion enabled doesn't make a difference either. Pc strafes are when you look at a 45 degree angle away fro the thing you want to jump on, and then sprint forward - turn - and jump. Console strafes are sprinting to the left or right in an arc - jumping - completing the C motion. Good luck
BTW - Heres a link to a good video for describing strafes.
[ame="
https://www.youtube.com/watch?v=aAv2fRwW3xg&feature=PlayList&p=1EEAA95D322ADE22&playnext=1&playnext_from=PL&index=41"]YouTube- ☆ COD4 Strafe Jump Guide PS3 / Xbox 360 ☆[/ame]