The light kit I'm using came with a strap on helmet mount and a tail light meant to be attached to the seat post. Using a rear rack with a bag on it blocks the use of the seat post. And I decided I like the headlight on the helmet better than on the bars.

So the helmet strap was tossed just leaving the light mount and tilt piece. Screwed it directly onto the helmet and cut off the screws nearly flush with the inside of the hard shell. Then drilled a hole in the rear of the shell and mounted the tail light. Then reinstalled the hard foam liner and all is good. Headlight is on solid, so is tail light. Although I think it looks kind of dorky. But it works great. I take off the headlight for daytime riding.

This works the best for me because I don't have to get dedicated lights for each bike. Especially as I have 4 bikes and 1 ebike.

Hey, if it works, it works. I'm convinced helmet mounted lights are attention grabbers, so I use 'em too although mine are much smaller and not quite bright enough to be ideal to-see lights.

So you have a screw in your helmet, pointing directly towards your brain?

Not something I would recommend.

I think helmet lights are great. I used to do it in the past and really miss the ability to "shine where I look". Your post is inspiring me to come with a solution that fits what I have on hand. If you are worried about the screw, you could substitute nylon screws and/or use 3M VHB double sided tape to hold light on.

Jut get a Light & Motion Vis 360 or 360+

Have been playing around with lights on my helmet for years. Started with flashlights; using rubber straps.
But I really like the helmet specific mounts. Niterider mount can ratchet up or down a bit; very secure.

Olight S1R on Lazer 02 by 1nterceptor, on Flickr

Rear lites test, East River path NYC by 1nterceptor, on Flickr

I have a double velcro rife flashlight mount. For $3 it works very well. Doesn't move around much.
https://d2ydh70d4b5xgv.cloudfront.net...17783e18d8.jpg

I use 2 lights for night Mtb rides. One on my helmet (using the factory velco & zip ties) and the other mounted on my bars.
The helmet light shines where I look and the bar light shines where I point the front wheel. The combination works very well, but if I had to pick only 1 light, it would be on the helmet.

I have this little light on my helmet: $1 on ebay, lasts for hours, recharge via microUSB, no battery to change, weight next to nothing.

Right.

That hard ABS shell may take some impact and distribute the impact some, but screws in the helmet wouldn't be my preference. Really short screws barely penetrating the ABS? Threaded into the ABS?

Personally I'd choose a quality epoxy instead.

I'd also like to see more tests with lights on helmets, potentially changing a flat impact to a point-source impact.

I use the Light and Motion 360 VIS and, being a clumsy oaf, can report that the rear light pops off its base rather easily. The front light is held more securely but shifts quite a bit when it is hit. Still, these hits are typically from the side, and it would be interesting to see what happens if the lights are driven straight down into the helmet.

No, I do not have screws pointing directly toward my brain. If you took time to read you would have found this little tidbit: " Screwed it directly onto the helmet and cut off the screws flush with the inside of the hard shell. " So the screws stick inside the hard shell less than 1/16" and there is 5/8" hard foam liner between the shell and my head.

The ABS is a little more than 1/8" and holes were drilled and threaded. Then the screws inserted and cut off inside then the foam reinstalled. I thought of epoxy too, but it doesn't stick to some plastic too well. The factory adhesive came right off the inside of the shell letting the foam liner come right out. That's why I went with screws. I do have 100% pure solids industrial epoxy that I use for boat repairs. But I went with a mechanical fastener instead. Could have used nut/bolt setup, but didn't have anything small enough in the shop.

There are some generics like it, but I'm using the Light & Motion Helmet Mount which will work with pretty much any light that comes with a bar mount. Never had it shift on me.

I won't say it's a bad idea to use a helmet light, as a lot of people are happy with them, but my experience on the bike path is that I don't notice them as soon as lights mounted on the bike. But I'm just one person.

I can't speak for others, but the light on my helmet is not for being seen, it is so I can see.

That makes sense. So these people I see with only helmet lights aren't aiming to be seen. Hmm.

In my opinion, the best setup is to run both bar and helmet lights.

Along with @DrIsotope, the primary purpose for a forward facing light on my bike at night is for me to see. This includes a 250 lumen helmet mount.

Being seen isn't a problem with 1450 Lumens.

Yep, K-Edge and helmet when riding one bike, fork leg and helmet when riding the other. I'm only throwing down a lowly 1000 lumens ( a 650 and a 350,) but so far it has proved to be more than adequate. I usually run the helmet light on medium, which is I think 500 lumens. The MTB'ers at the LBS recommended the dual-light setup, and it's perfect.

About the seeing over being seen: sticking up off the top of your head, even a lightweight high lumen lamp is REALLY noticeable after an hour or so. If I had to ride with the helmet light every day, I think I would develop beefy neck muscles.

Cars really slow down as they approach me with the helmet light. The real reasons I put the light on the helmet are 1) I like having where I look illuminated and 2) I don't need to buy multiple lights or mounts for multiple bikes and switching lights between them. I did buy a few of the rechargeable blinky tail lights to mount on each bike because they are inexpensive. Like to screw them on so they don't disappear while I'm in a store.

BTW, I noticed the pictures of helmets in this thread are the light weight road bike style helmets with lots of ventilation and some (like the Schwinn) have just a thin foil plastic covering. You might want to reconsider those style helmets. In a fall caused by hitting a pot hole or curb, they are fine. Being hit by a car, those helmets break apart after the initial impact (and there are usually multiple impacts in that type of accident) leaving the head unprotected. A study I read online indicated that helmets with high ventilation provide the least protection, where extreme sports helmets like the black one I have pictured provide the maximum protection. I don't feel my helmet is hot, although that is often a complaint. The study also noted that those speedy looking helmets actually have more drag due to the irregular surface than a plain old smooth BMX helmet.

The Lazer 02 helmet is a good example of a manufacturer adding reinforcement inside the foam to "prevent the helmet from breaking apart on fist impact". This helmet typically sells for $100 in size Large. So if you want a road bike helmet that will stay together, its gonna cost about 5 times the price of a BMX helmet and probably not protect as well. And make no mistake, that Lazer 02 is a mighty fine helmet. A good Commuter/bmx/Multi-sport helmet can be had for as little as $25. And they come in bright colors now, not just flat black. In fact I was thinking of buying a new one in white or bright red. That Bell helmet I use is probably 8 years old now. Cost $50 now, I probably paid about $15 for it back then. There are lots of knock offs and copycat Bell helmets out there now with improvements.