I think (1) is preferable to (2) because the option to select a printer at print-time seems to me extremely useful. The folder watcher in option (1) won’t be as reliable, but I don’t think it’s a burden to insist that people print to a temporary folder that is different from one’s documents folder. It seems to be inherently dangerous to use a system like this that deletes files (as this one does with the output print file) in a folder which also has files that you want to keep. There’s too much risk for something to go wrong.