Maximum illumination is a function of the light. Floods do well almost anywhere because the illumination is a big, even hemisphere projecting from the pod. But higher positions are better because they create smaller shadows. The shadows can hide a hazard behind a crest. Spots are easier to use mounted lower because the chances you'll blind someone are lower. It's hard to do on a motorcycle, but in inclement weather, having a light mounted above the eye level can produce more obstruction through reflections of falling rain or snow than actual illumination. Normally, anywhere from the handlebars to roughly the top of the mudguard is a good height to mount them. Protecting them from crashes is a whole different challenge. First point of hope is that most good well-made LED pods are designed (and destined) to be placed on the outside of the vehicle, in harm's way. So they feature robust casings and tend not to break as much as scuff in crashes. But the trick is to mount them as inboard as possible. On a motorcycle with a comprehensive crash bar, you might ensure that all the light pods are inside the bar so that the bar takes the big impacts in a crash.
Generally not enough to notice since each pod weighs between 400 to 800g on average. Obviously having four lights means you now have 3kg of light and wiring tacked on, but I would be surprised if you'd notice the difference in normal riding.
Like we noted before, in general, LEDs are so effective at producing light that their actual current consumption and load on the system is generally negligible. Most of the lights barely need 5A, which is usually the weakest of your bike's circuits, the cigarette lighter charger socket. Even with four lights, you'll be running barely 8A which is easy to handle. So in most cases, unless your battery or regulator-rectified has a problem, or you have an old bike with a weak alternator, LED lights will not cause problems. If you're adding other kinds of auxiliary lights - HIDs, high power bulbs etc - you need to pay attention to the ampere and watt ratings and then check your manual.
Unless you're turning your motorcycle into a Christmas tree, you add the lights for a purpose. If you're going slowly off-road on a trail, you'll need floods. If you're looking for long distance vision in the night, you'll want a hyperspot or spot depending on your specific requirement. That's the first thing, what is the light supposed to do for you.
Then comes the logistics of it. That's amperage and wattage and whether your motorcycle's electrical system can handle the load. Usually, the LEDs are so efficient that this is a non-issue.
Then based on both of these considerations, budget and aesthetic predilections, the actual brand and model selection.
Most LED lights do not actually include the full mounting hardware and you'll need to make separate purchases for that. Most good brands do include wiring, instructions, and switches though.
The trickiest bit though is to find a power line the lights can use. Most will mount the battery directly for power with an inline fuse. But they all need switched power. That's a power line the light can tap into which comes online only when the ignition is turned on. This part has to be attacked carefully. If you cut or splice a wire, you could void your warranty. On most touring machines, you already get uprated alternators for heavier power draw. What you're looking for is a blank GPS power outlet or secondary (unused) cigarette lighter socket outlet. If you can match the connectors (there are many standard types across the OEM ranges), you can use the bike's wiring as it was intended without any cutting or splicing. Your option is a PosiTap connector that everyone seems to include which neatly drills a tiny hole in the switched power insulation. It's a neat solution but you can still be accused of cutting into an OEM wire for warranty purposes.
On the Ducati, we found switched power in the GPS power socket which is a Deutsche-style male connector mounted next to the headstock. We located an unused female that we wired the switched power line into. Plug it in, and we have power without cutting anything.
