Use WMV or AVI output format - these will take longer than MOV but will result in a lower video file size. You could also render your scribe via sho.co which will allow you to download your scribe as an MP4 video file. This file type is the smallest of all the video format options.
Choose a lower output resolution, e.g, choose 720 standard HD (1280 x 720) instead of 1080 full HD (1920 x 1080). Smaller output resolutions are 360 web/mobile (640 x 360) and 640 normal (1138 x 640).
Use a lower output frame rate - this reduces the number of frames per second of video and will result in a smaller file size.