This guy sold me a set of relays over 5 yrs ago they have outlasted the OEM ones x2 a very nice guy and very helpful as this qn comes up now and again I have added info to the non OEM parts too.
I know there are other relays BUT some do have diodes in them and will damage YOUR Guzzi some DO NOT have resistors in them which is the cause of premature failure.
THESE work and are inexpensive enough to get spares to use as:-
Dip/main switch relays small enough to fit inside the headlamp
Dan does have the specific information which is why I e-mailed him for his permission to post his Frequently asked questions link, which he gave happily.