You could certainly do this, technically. What's driving you to record at so much lower resolution than live video?
In my experience, people will drop the resolution for the live view stream, but use the full resolution for the recorded stream.
Think about while you are watching many cameras on screen at once on a split screen view. You won't be able to see the full resolution of each camera. If you blink, you miss something. You want to be able to go to playback to see what happened, etc., and have the resolution to zoom in. Usually you zoom in digitally for playback, but not on live view.
Thus, high resolution for recorded, and lower resolution for live.
This also helps to mitigate CPU load on viewing PC.
As John stated, if you need to conserve storage, lowering the frame rate for recorded video is the first line of defense before lowering the resolution.