Swinada I think when trying to figure out how to connect auxiliary lights it helps to not only have a plan for which wire goes where, but also to have a plan for what the lights are supposed to do.
Why are they being installed?
a) To make it easier to be seen by other road users day or night? Running those on low beam makes sense, so the road users don't get dazed. Like daylight running lights on cars.
b) To see farther down the road at night and avoid animal strike? Running those on high beam makes sense, as using those tends to be without oncoming traffic (consult you local authorities if needed).
The lights in a) may only be little 10watters to achieve that and work perfectly well. They won't be of much use on high beam anyway, so may as well switch off on high beam.
The lights in b) would ideally be more powerful and certainly aimed to maximize down-the-road performance. They would be inappropriate or at least wasted for low beam use.
If you want the one set of lights to do both jobs then a dimmable arrangement like for example a Skene system or some of the Denali series from Twisted Throttle could do that. Low beam could run at 10-20% (so you can be seen), flick to high beam and they go to 100% (so you can see) or switch them off with a manual switch.
Running 2 sets of lights is another way and what I tend to do. A 5 pin relay with 87 and 87a pins available can do that. One set of lights per pin.Triggered by the high beam wire, the little lights can run on low beam, then flicking to high beam they go off and the big lights come on. A handlebar switch spliced into the trigger wire means you can turn them all off if you choose.
