I'm replacing two(!?) sliding glass doors with one new one. The new one will be flush with interior drywall - but this install will leave a 4 inch gap between the brick and exterior frame of the new doors. I do not wish to change the current 2x4 framing for the new door (trying to keep it simple). What is the best way (or options?) to "fill" in the gap between the brick and door frame - original setup only had a 1x4 covering the masonry/brick gap? Thanks!!