FCP2 and Compositing Work Flow....

Recently got the FCP2 suite, I am curious as to this - what is the best workflow for compositing green screen work -
I have nice plates, however - they will need to be color corrected to match - as do all the shots being keyed - I realize color does NOT like stills - thus should I render each plate out to a movie??
What about color's limit on superimposed shots with opactiy?

Just really looking for a good workflow pattern without wasting too much time experimenting right now....suggestions welcome.