I have now tried the oven a couple times now and like it but learned a few things.  Just thought I would share what I think, then others can correct me or make suggestions.  
The oven works better with flame than the heat of the coals.  I think because it reflects the heat around the pan better when the 'heat' is coming from a flame that is dancing around rather than coals at the bottom.  
I think a oven themometer would be a good addition.
I found that turning the pan jsut a few times was better than rotating lots.  
To really make it work well, have your wood cut and ready and sit and feed the fire to keep it constant.  
I made some brownies that my family loved the last time we went out.  It was a little cool and warm brownies hit the spot!  My family is now willing to overlook my testing backpacks around the neighborhood. ::)