Did you run the above tests against a fully charged battery (overnight or longer on a low current battery charger)? If not, they're pretty meaningless, as the condition of the battery, not the voltage regulator or generator, controls the final voltage. The terminal voltage of a fully charged, good condition 6V battery should be 6.3V or so with engine not running. Voltage from a properly adjusted voltage regulator at cruise speed against a good battery should be 7.3-7.5 volts.
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!