P: Download 1:1 Previews for Offline Use for Select Photos

I would like to be able to manually select a set of images and "Download 1:1 Previews" for them so when I travel and don't have internet, I can continue working off of them as full-res images and zoom in tighter to them.  My use case is that I don't need my entire catalog downloaded to my laptop, just a subset of them at a time as I am working on a large project and Cloud doesn't have the concept of multiple libraries. After I select this option, I would like them to stay until I manually remove them, and I would like them to automatically update if I edit them on a different device.  After I connect back to the internet, of course all changes sync back up to the cloud.  I would like this option for both Desktop and Mobile.  Thank you for making Lightroom better!