I realize that RTSP uses RTP, I'm wanting to compare is plain RTP over UDP vs RTSP using RTP. This would be on the publishing side of the stream and in this specific scenario bandwidth is extremely limited. Will removing RTSP from the mix actually gain me anything?
RTSP really only deals with the setup, pausing, resuming and teardown of the stream. This bandwidth is usually tiny in comparison to the media (which is sent over RTP).
So no, removing RTSP from the mix won't help you.