I am currently testing out AppX for a customer Appx is fairly easy for small applications such as Adobe Reader and so on.
does anyone have any experience in packing larg
Converting the packages is now much easier with the new free Express edition from Advanced Installer, developed in partnership with Microsoft.
It has a GUI that allows for advanced customization of the APPX packages, without requiring you to have knowledge about the internals package schemas.
If you have any questions about it, let me know, would love to help.
Disclaimer: I work on the team that builds Advanced Installer.
With Desktop App Converter, making customisation while creating AppX packages is not straightforward. It may be easier to use one of the application repackaging tools which enable you to capture any number of MSI and make the necessary customisations, including any changes to the registry or file system. Here's the list of some of such tools on Microsoft website: https://docs.microsoft.com/en-us/windows/uwp/porting/desktop-to-uwp-root