I could have done this about six different ways. Monster makes their brick arches in one radius. This works fine for the windows and man doors, but the radius of the baggage door arch is far greater. Looking down at my coffee while at a light yesterday the thought occurred that the top would make a great template and it turns out it is really close.
I cut the arc out of the top, penciled in the correct radius and placed pairs of brick into tacky glue.