Well.... I have to say that I am very happy with the solution I came up with, although it was painful. Basically I had to make the firewall top stiffener all over again... this time... to specs! I also had to cut the flanges of the center channel's side braces to accomodate the new setup. I would then have to drill an L angles from the side brace to the stiffener. I decided to make the L angles of 0.040" (same as side braces). Moral of the story... check and re-check ALL dimensions.. 5 mm can make a big difference!
