You can't change the sort order of a smart collection. However, you can select all or some of the photos within a smart collection then make a regular collection by clicking on the + button on top right corner of the Collections panel. A dialog will open which allows you to make Virtual Copies of the selected photos. Doing so isn't absolutely necessary but it doesn't hurt, especially if you decide to make further edits to the photos that will be specific to the slideshow.
Since a smart collection is a search, you can also use searches/filtering to create a regular, or static collection (it doesn't update dynamically/automatically like a smart collection). A nice way to do this is with the plugins Any Filter or Data Explorer.
Any Filter lets you save searches, so you can re-search for criteria at discrete times and save as a regular collection.
Data Explorer can, for example, find all collections, and then isolate and save a smart collection as a static/regular collection in just a couple of steps. I used it to convert several smart collections to regular collections, and to save a lot of publish collections to regular collections too.
that's great. Just the ticket! Thanks
I realize it's an old post so hope you're still listening. With the latest version of CC if I do what you suggest can I then setup a sort of auto sync from the Smart Collection to the Regular collection? Just like auto import from a watched folder? Which by the way, can I have a watch folder setup so files imported from the watch folder can be automatically added to a regular collection without the use of any criteria like what's used to create a smart collection?