How can you set the height on a text entry field? The answer, you can't! You can only set the width. The module description page for tk::entry doesn't list "height" as an option. These pages are the best reference for what a widget can and can't do.

UPDATE: I should add the "configure" method can only configure options that are a subset of the widget class you are working on. It can't configure for options that don't belong to that class.

Have fun!