Leaning

I would call myself a novice to the FS series of games, having flown in FS2004 with my PL for almost a year now. Needless to say, lots of questions still arise on a daily basis ;D.
I just have a quick one regarding mixture control. Say I'm taking off in a Cessna 172 from an airport that sits at an altitude of 4500ft. For takeoff would I want a full rich mixture, as if I were taking off from sea level or from below 3000ft, or should I lean it first to what I would if I were in level flight at 75% power at that altitude?
Thanks!
I just have a quick one regarding mixture control. Say I'm taking off in a Cessna 172 from an airport that sits at an altitude of 4500ft. For takeoff would I want a full rich mixture, as if I were taking off from sea level or from below 3000ft, or should I lean it first to what I would if I were in level flight at 75% power at that altitude?
Thanks!
