Have you thought of using the place geometry manager instead of the compass points?

For the couple Perl/Tk that I've developed, I found it useful to use a graphics program suck as Paint Shop Pro or Photoshop to lay out my widgets and then use the ruler features to get my X-Y coordinates and use the place method. I found it easier to actually place my widgets exactly where I wanted them, rather than rely on the compass point method.

Of course it's going to depend on how many and what type of widgets you are using.

Hope that helps!

Update: s/place command/place geometry manager/ - thanks to anonymous monk.