I remember riding with cats that used these:
I was never much impressed. The lamps so often wiggled&squiggled around and uncomfortably dropped and/or pointed in an ineffective direction...
Yep... I get ya. I wrapped reflective tape around the base. I also used a Head Lamp powered by a 6 volt Dry Cell on my belt. The things we did. Flexible reflective clothing was around but out of reach till the late 70's. One of the guys I rode with had a Reflective Jacket from the airport. Wow... It was really trick...