Kyle, Gerardo 

Today we applied Ultratape against the spool and both sides of the stiffener around the entire periphery, in effect, bagging the inaccessible space between the stiffener ring and the spool.  Next, we made a small incision and inserted a 1/4" poly tube to allow us to pump the inside of this "tape bag".  The overall seal wasn't very effective due to the lack of access in the area of interest - between the spool and the support gusset which is also the area of the leak - but we were able to achieve < 300 torr inside the tape bag.  As expected, the Y-mid pressure responded accordingly.  

So, at this point we have the leak location narrowed down to approx. 1" x 3" at the overlap of the spool seam weld and stiffener stitch weld (poor fabrication technique!)  We have some ideas of how to better access this area which we will need to do before applying epoxy or equivalent to seal the leak.