On the iPhone Duo the standard "Edit" button for navigation bars is a text-based button, and text-based buttons are not pushed to the vertical toolbars on the Duo. This looks sometimes silly, if it is the only remaining button that can not be placed in the vertical toolbar and which has the result that an almost empty horizontal navigation bar must be kept visible as well.
So I guess it would be good idea to have an icon-based replacement for the Editor button to avoid having two toolbars on the Duo. Is there a best practice for the icon to pick for such an edit button? Would be "square.and.pencil" (SF Symbols) a good choice? Or better the "pencil .circle", because the "square" one is often used for text-based input? Anything better?