Well, I haven't done any beamshots yet as I'm just now waiting for my first serious order of flashlights to arrive, but, based on my 45 plus years as a professional photographer I would shoot the dimmer light first and bias the exposure to show that light as somewhat underexposed but still showing some dim detail. Then, if there is a very great difference in brightness between the lights, the brightest one would probably appear overexposed and washed out. That way would probably give the viewer more information that he/she could relate to.
The problem we run into when photographing scenes that have a great brightness range is that the human eye is capable of discerning details in a much wider range of brightness than any film or digital imager can.
Actually, you could also expose for the brightest light with just a little bit of overexposure washout on that picture and then use the same settings to shoot the dimmer lights and let them go as dark as they need to then post both sets of pictures so the viewers can see the brightness range from both directions. Making these decisions is so much easier with the instant feedback of digital than it was in the film days.
EV_007 gives real good suggestions above too. I'll look forward to seeing your results.