When you export your film, you should have the option to export in various settings. You might want to do an export with half the usual dimensions, for example, which will drastically reduce the size of the video file. You probably have options to reduce the overall quality of the video, as well, which can often be fine if the video is just being used as a reference.
If you use Adbobe suite, you can do all this through Adobe Media Encoder.
If you use Apple, I think it's Compressor.
Some peeps find the free Handbrake to be useful for this.
Vegas prolly has its own things.
You should check with our composer to see if (s)he wants a timecode burnt into the video, btw. That can be really handy. It's trivial to do this in Adobe. Unsure about other software.
Fwiw, Microsoft Skydrive can take a file up to 2GB in size if you have a problem squeezing down to your requested 700mb.
Hope that helped
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