i'd run them straight from the battery and have the relay connected to one of the high-beam wires. might also want to wire an extra switch between the relay and the high-beam wire, so you can turn the hellas off while using high-beams if needed. IMO comes in handy on heavily foggy nights.where i live, the switch is compulsory anyhow. the relay doesn't draw much current either, so the slightly reduced output of the standard high-beams shouldn't be noticeable.
Doesn't running them straight from the switch also result in an high voltage drop due to high resitance?
Bought it, drove it, broke it, fixed it, drove it, broke it again... Love it!