Julian,
While admittedly not the standard high beam flash that is normally associated with a flash-to-pass action, I humbly contend that 55 W DRL’s flashing on and off will prove sufficient. 😁
The DRL‘s are controlled by a voltage-sensing module that closes a relay when it senses the charging voltage of an alternator. The flash-to-pass action opens and closes a second relay in the DRL circuit that interrupts the DRL feed coming out of the first relay.
Larry