If you are looking for a handy tool to tell screen sizes or even determine what your current screen size is before publishing your articulate output, here is a handy tool I found for such a purpose.
It is called viewportsizes and shows a downloadable list of devices and their screen sizes. Alternatively, you could add "/mine" (without quotes) to end of url or just click view my port size and it would tell you your current screen size.
I've found this tool very useful. Also wondering what other such tools people are using to help in determining optimal screen sizes for .story outputs.