So here's one example:
These settings are a little higher quality than what LumaFusion suggests. The resulting file is still much smaller than the original which makes me think I still have some play room. Again I am merely using this program to set a solid constant framerate, I need to keep the quality the same. Also in the additional options, you'll see the recommended option of keyint=48. I understand this makes for smoother scrolling through the video footage in LumaFusion though I do not know why the number of 48. I see in Handbrake there is, for example, a preset for Youtube 4K which has this info in the additional options: keyint=30:min-keyint=15:ref=1:bframes=2:b-pyramid=none, which I currently have no idea what all that means.
At any rate, I figure this would be a good opportunity for exploration and collective sharing of presets for best usable quality.