no, the menu writer wizard does not allow to set a specific width for each menu item.
this need to be done outside of the menu writer wizard by adding an inline width style to the menu items to override the menu writer css.
for example, to change the width of the home element. change:
<li><a href="index.htm">HOME</a></li>
to:
<li><a href="index.htm" style="width:50px;">HOME</a></li>