Full body blue or green screen is a challenge. If you don’t have a waveform monitor I suggest you rent or buy one. If will show how even the light is on the background. If you have a straight line on the waveform, you key will be more consistent.
That said, I think you’ll need more instruments to light the floor since your key and fill lights are probably washing out its color.
As for keying with DV, search the Final Cut Pro forum for DV key and you’ll find a lot of information. There are some specific plug ins that will really help.
John
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