I do like all of the MacGyver-ing that all of you have done.

RockBros has an excellent helmet with built in light.

https://www.ebay.com/itm/RockBros-Ro...arms=aid%3D111

There are so many bicycle headlights that can be utilized, on the handlebars, or the stem, or front brake caliper bolt on ancient bicycles.
You also have many ready made, flashlight mounts that can be found by searching twenty or so ebay pages SEARCH: china bicycle ON EBAY(search all categories).
Then further search "view other items" within these mammoth chinese ebay powersellers...........hit the see all categories on the left side......see Sporting Goods....select Cycling, bicycle parts, bicycle accessories, bicycle lights, etc.......whatever relevant heading, and look through the offerings..............pay attention also to the other sellers' offering the same item at equal or lesser costs.........repeat the process.......... ......you will be surprised at the huge breadth of different mounts, lights and everything you can imagine.............yes, it might take you searching several days, of one hour of searching, but you will find plenty of handy items that you cannot find
at the LBS, Target, or Wal-mart. Buying these New chinese goods via ebay offers you significant protection from being totally ripped off because you will be protected if for instance that the seller doesn't ship you the item----Paypal and ebay will protect you the purchaser. Now you're outta luck if the item is just ineffective but accurately pictured and in otherwise good condition. Obviously, there are many items out there and in retail stores and also local bike shops that "promise" more than they deliver as far as practical functionality. It is your duty as a shopper to determine that and do your due diligence and decide accordingly and determine whether it is likely just hype or something that might actually have practical functionality that will benefit you and make your bicycle riding more enjoyable.

......Heck, even something as MacGyvered like two stainless steel radiator hose clamps from any auto parts store or wal-mart auto parts section, will snugly secure any of those four inch long, round metal 9 LED, three AAA battery flashlights that Harbor Freight sells in packs of two for about $1.99...........they once had a regular FREE COUPON with any purchase for just one of the all Black version flashlight.
You should really look at the many ready made BICYCLE lights from the many mammoth China based EBAY sellers. You'll find so many lights under $10 and none of the lights will be more than $20. I don't have to tell you that the exact same light might be in Wallyworld or your LBS for much much more, and you'll find a larger selection from the ShenZhen, and Hong Kong based mammoth Ebay sellers rather than locally.