Keep Splitting as needed (always auto-split)

Right now when I’m typing a long post that I want to split, Typefully keeps annoyingly suggest that I either upgrade my Twitter account to premium (don’t want), or auto-split. It’d be great if that could just be always on for the current post (or always on until I turn it off), because now I have to click auto-split every single time I type too much! I tried clicking on the “Split Automatically” (which is hidden by the too-long-for-Twitter message), and, well, it doesn’t seem to do anything. (I don’t know what “split automatically” is supposed to do, but it’s not what I want it to do.)