Blairscomp.7z Link

: Set to "Solid" for the absolute best ratio, or a smaller size (like 1GB) for a better balance. Does 7z compress better than zip? - Microsoft Community Hub

: Use the command 7z l Blairscomp.7z to list archive details and check the "Solid" status line. Optimal Settings for Maximum Compression Blairscomp.7z

: Modifying or adding a single file to a large solid archive can be slow because the entire solid block often needs to be re-processed. How to Manage Solid Content in 7-Zip : Set to "Solid" for the absolute best

You can control how "solid" your archive is during the creation process or check its status afterward: Blairscomp.7z