I have been looking at the various places to mount LED spots and have now fitted them in a location that I have not seen used before. This position will not suit everyone but it gives another place for consideration.
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My aim was to get higher visibility to other road users rather than improved road illumination so I have set them at a pitch angle that avoids blinding any oncoming traffic and they are on whenever the ignition is on. They could just as easily be triggered by the main beam power to give true spot use.
As an alternative to lights, consider slathering your helmet with high-quality hi-viz SOLAS reflector tape. It's the highest point on your bike, can be seen from any direction, can't blind drivers, and is maintenance-free and relatively inexpensive. Putting some on the bike wouldn't hurt, either. Here's my helmet and bike. (In addition to the hi-viz tape, my winter hand muffs and apron are retro-reflective).