Video output settings for small file sizes

Dear all,
I am using Blender’s video sequence editor to create tutorial videos for university students. To keep the file size small, I am looking for good video output settings.
A short test video clip of 10 sec (250 frames, Full HD resolution, with Audio) with default settings in Blender gave me a 1.2 MB mp4 file.
By tweaking some output settings I was able to reduce the file size to 830 kB.

My current settings are:

  • File Forma: ffmpeg video
  • Video Codec: H.264
  • Output quality: Low Quality (below that it starts looking really cheap)
  • Encoding Speed: Slowest
  • Keyframe Interval: 25 (i.e. 1 [email protected] fps)
  • Audio Codec: mp3 (mono, bitrate 128)

Are there any important settings that I missed and what are your settings to create small but reasonably good looking videos?

Update (in case people from the future have similar problems):
Following advice from stackexchange, I was able to compress the 1.2 MB reference file down to 474 kB without significant loss of quality.
The command is the following:
ffmpeg -i input.mp4 -vcodec libx265 -crf 28 output.mp4

Is it possible to obtain this type of compression directly from Blender?