I plan on doing the minimum required to get her up and running, I'm not planning for a full strip down restoration rebuild, she will be a riders bike with all the history, scratches knocks and mods that have been done over the years. Well that's what I'm aiming for, that will probably change in time.
A barn find is a lovely idea but why did it get put in the barn in the first place? I always suspect that it is because someone was totally fed up with the unreliable, worn out piece of junk always letting them down.
( I recently found this the hard way with a fairly original 1936 - non Vincent - bike that I bought. It was ratty but started and ran quite well. When trying to fix a few minor faults it was apparent that it was worn out and had been bodged at some point in the distant past. Continued use would have led to frustration and more damage)
The finish and patina is purely a matter of choice but I think that you should have a good look inside the case before trying to use it. Alloy idlers, sludged oil ways, worn out primary chain are all things that shouldn't be ignored.