Light matters. Seriously; it REALLY matters.
When practicing night ops, we have a bit of a conundrum; light is both our friend and our enemy. It allows us to see, but it gives away our position. Obviously, the answer to not giving away our position is to not use light at all, but in near or complete darkness, shooting a bow and arrow accurately is pretty much impossible with any real degree of consistent accuracy. Given that, the ultimate answer is lightweight night-vision goggles, but that is a serious chink of change that many people do not have.
That said, adding a flashlight to a bow is a great solution to the problem. The hardest part is how to add it. Several options exist, from paracord to zip strips. anyone interested in tactical anything is familiar with paracord, and would feel lost without having at least a bit of paracord on their person at all times. As such, this is probably the best field option for last-minute retrofits. Zip Strips also work wonders here, but these are not often carried around and degrade in sunlight over time far faster than paracord. A better alternative to the two is to use Velcro cable-ties; these lightweight, thin, and durable ties can be kept on one's person or permanently wrapped around a bow for use as needed.
So, as I said, light matters...
I pulled out this cheep Nebo LED tactical flashlight I have that I received as a freebie a couple years ago to test out. The problem? It is about 50 Lumens which; I remembered after the first test shot that this is the reason I don't carry it and bought the Mini Maglite instead. I could see targets within 10 yards somewhat well enough to shoot with relative accuracy, but distant targets were barely illuminated and accuracy suffered horribly. I was better off closing my eyes for 5 minutes and then opening them to shoot in the ambient night light.
I then pulled my Mini Maglite Pro 226 Lumens LED Flashlight off my belt and affixed that to the bow. WOW what a difference an extra 176 Lumens makes! I could see targets 40 yards out well enough to shoot with good accuracy, and I am a bare-bow shooter. Additionally, tactical flashlights for mounting on firearms are often used to blind opponents, and thus are usually a minimum of 150 Lumens, with most being 200 Lumens or more. these flashlights often add a strobe feature to further blind opponents.
My take away? If you want to add a flashlight to your bow for night ops, get one that is at least 200 Lumens. A Mini Maglight Pro will work wonders and provide all the basic functionality needed to shoot at night for short to medium distances. A tactical flashlight such as the Nebo 5630 Protec Redline 220 Lumens LED Flashlight would be a far better choice.
One additional bit of advice; mount the flashlight roughly where the sight would be mounted. Mounting the flashlight to the stabilizer bushing provided a pretty poor angle of illumination for distance shots.
50 Lumens photo vs 226 Lumens
The photos below show the results of shooting with each flashlight. To illustrate the illuminating properties, they were shot illuminated by the respective flashlight as well.