Does anyone know how to manually associate particular file types with Windows Preview Handlers so they display correctly in the preview pane?

I save my emails as .eml / RFC822 format. This is so I can use the email metadata columns in Windows File Explorer. I've also used Microsoft's Preview Handler Association Editor tool (old but works well, including up to Windows 10) to associate .eml with the Microsoft Windows Mail Mime Preview Handler. After this change, emails display exactly how I expect them to in the preview pane so I know it all works. 

I now have another machine I want to make the same changes on, but can't install the .NET dependencies to make the Preview Handler Association Editor tool run. Is there a simple way of making this association without the tool? I appreciate that it will probably involve registry edits, but I can arrange for that to happen, even if installing .NET is verboten.