Recently I was working on a couple of FileMaker 13 projects where in earlier versions, a Modal window would have been the best method for getting the user to complete the process. Since this was 13 and we now have the Popover I thought a Modal Popover might do the trick. I liked the result better then the modal window. It seemed a bit cleaner and kept the user focused on the current window.
Attached is a demo file that shows how to do this. It's fairly straight forward and the process can be expanded to add a slide control to the Popover. I hope you find this helpful