Running- - - -not running - - - - -doesn't really matter. I've done it both ways for over 50 years with no noticeable difference in the results- - - -it either works or not depending on the internal capability of the generator. I am partial to using an "analog" volt/amp meter, (with a sweep needle) as some digital meters respond too fast for a vibrating contact regulator and just end up indicating gibberish instead of a usable indication of current or voltage.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!