I ended up breaking out the original oxide red acrylic paint and VERY LIGHTLY dry brushing some on to lighten the wall.  This seemed to work great, so I lightened the whole wall in this manner.  

This brings up an important point.  Unless you are extremely polished, like George Sellios, you probably won't be able to get the same results on every building- even using the same methods.  Sometimes you may get a building that looks too light and sometimes it may look too dark.  Experiment.  Some of the best looking buildings I have made have come about through trying different methods. 

The building at bottom right is one such case.  I didn't wait long enough between my base (orange) coat and my mortar coat and as a result the colors blended together.  The result, after applying some black powder, was great!  The only downside is, even if you get a cool result, it's hard to replicate it because the look wasn't planned.  But the moral is- don't be afraid to try things!

Though the main wall color was finished, more detail weathering was added; mostly with powdered chalk and a very small brush.  You can see some of the detail weathering at left; exhaust marks and rust streaks. Unfortunately I don't have pictures of this additional weathering- but- my next clinic will be on detailing and finishing off your wall sections.