SailingAway wrote in post #18146317
^^^What Al wrote!^^^ You need to match your editing project settings with the dimensions of the original footage for best results.
The MOV bitrate specs aren't bad, but it doesn't tell you what codec is within the MOV wrapper. Oh, this is from a camera recording? Most likely it's an
MP4/h.264 in the MOV.
this is what I found online ...
Canon 5D Mark III Basic Video Specs
•1,920 x 1,080 (Full HD / 1080p); 1,280 x 720 (720p); or 640 x 480 (VGA) recording
•MOV file format, with variable bitrate MPEG-4 AVC/H.264 encoding
•Choice of two compression types; ALL-I (intraframe) or IPB (intraframe)
I'd try a render to the Youtube 1080p settings and see how that looks for "reducing the file size as much as practical" but preserving visual quality. Check the bitrate, see how it looks.
will give it a try 
For "best possible format" it's still not clear what's going to produce the best results. Skip most of what's on the "Save as Video" tab. Try AVI/free MJPEG, MOV, AVI/h.264, MP4/h.264, and WMV and compare bitrates and appearance.
looks pretty respectable and likely to look better when I get the input and output frame settings corrected for 1080 instead of 720
***edit***
It appears that Movavi Video Editor isn't well supported - no manual available on their web site, though there is for their other products. You might want to ask about the best quality for mastering / archive by emailing support. Or maybe just get into an editing platform that is supported and better known, where you can find a user community, youtube videos, etc.
There are probably better ones out there, I had been using the Movavi Video Converter prog for a couple of years and was doing all I asked for converting between different format types ... have only within the last week paid for and downloaded the editor version of the program.
Clicking on the manual in the help tab takes me to an online manual. There is also chat and email support available on the page.
And unless I get into Pro video/editing, this should keep me out of trouble 
Dave