hi bubbajunk :-)
On the toolbar, on the right side of the SC window, the icon for "Text Object" will display a sort of an options/settings panel. You can set the colour of the border there - but I dont see any option to change the width.
EDIT/ always forget something:
If it's a text box that you've already made, you'll have to click on the ObjectMode icon on the same toolbar (Arrow with a red "O").
Then click on your text object. Then edit using panel as described above.