These strobes are awesome - I've got two white ones for night commercial work. I've had them 2.5 miles away and still visible. So small and light and so bright.
I wanted to be able to easily take them off when I wasn't using them so the drone can stay as close to stock shape and weight as possible, so I attached them with Scotch Dual-Lock (should be available somewhere local too):
Amazon.com : Scotch Reclosable Fasteners, Clear, 1 x 3-Inches, 2 Sets (RF9730) : Scotch All Weather Fasteners : Office Products
It's stronger than velcro and doesn't lose grip over time.
I've never had trouble seeing the flash at night, but know that if you floor it and the props enter your FOV, you'll probably see them. When I'm filming for keeps, I tend to fly slower, and it's not been as issue. Surely positioning is important here; I've got one mounted on the very top next to the DJI decal and one on the bottom of the landing gear all the way toward the back. My intent here is for a strobe to always be visible in every direction while keeping the flashes away from the camera and the front landing gear which could reflect back on the camera. Another bonus is that when the strobon's not attached to the bottom, the aircraft still sits square on its four pads, so no complications with landing. These are a fantastic addition and SO cheap - absolutely no reason not to get them!
