I did something similar, only I used a 1" PCB elbow and installed a P60 in it. Built a generic collar that screws onto a microphone gooseneck, shown here with my L4 mounted for additional light.
the contacts being mere alligator clips, a couple loops of teflon around the reflector and forced it in with a vice, works well.
Runs on a homemade 5V stepdown from a 12V supply, which results in about 500ma foward current. Good thing with incandescents is the carelessness of heatsinking.