I think the UK also still requires an anti collision light for helicopters to be red. As far as I know, navigation lights are only mandatory by night here, they are all but useles by day anyway.
I try to use my own good judgement as to which lights should be on, the brighter the better in most circumstances.
A good few years ago the RAF began to fit selectable combined red/white strobe anti-colls to Puma aircraft, replacing the older filament type. I flew the first aircraft fitted with one back to UK from Germany. On arrival at Manston, ATC told me to switch the red strobe off whilst taxying, as it was too bright in their opinion, even by day! I explained that it was either that or the even brighter white one, that's all we had.
We used to use the white mode away from the circuit, as it was far brighter, red was selected with the pre-landing checks. We liked to use the searchlight at low level as it reduced the chances of a birdstrike.
The HISLs on the a/c I fly these days are so bright they light up the ground by night from 2000ft, you could probably take photos by them! They aren't supposed to be used at night or IMC as the reflections into the aircraft are disorientating to the crew and possibly make some pax fall to the floor, twitch and pee their pants.