Overblowing the SANS instrument produces a sound like the last words of a pig in a slaughterhouse. It isn't a musically effective option, at least not on mine. I find it works better just to go with what seems to be the basic character of the instrument and use a rather soft reed which makes overblowing even less feasible.

Notes start and stop a lot quicker on the chalumeau than they do on my Turkish G clarinet (or any other clarinet I've played). It's like a bagpipe chanter - you can make much more complex gracenote combinations clearly audible.