Electrically the MC11 and NC19 are very similar apart from the obvious difference, two cylinders not three.
The other differences I've found so far are:
1. NC19 has a radiator fan, the MC11 does not.
2. MC11 has an electronic speedometer and associated over speed lamp, the NC19 does not.
3. The MC11 has a fuel pump, the NC19 does not.
The fuel pump surprised me, do any of the NSR250s have one?
All I need to do now is find some software to start drawing up the diagram....
Also you might be interested to know that I've managed to find a article on the MC11 on Alastair's NS400R web site at www.elmarie.dsl.pipex.com/BikeOct85NS5.htm