I have been playing around with this idea also, with my Pershing and Tigers. I had a thought of putting the IR bulb in a tube (6mm for rules), and the flash behind the IR, but use several clear fiber optic tubes, like the ones I use on my Pershing headlight and tailights, Put those around the tube the IR bulb is in. Just and Idea, I havent done the measuring of it yet. It may not work at all. I have messed around a little bit with using the fiber optic in the barrels already. I have about 50 feet of clear fiber optic tube, I thing you can get different colors also. Just an idea. I never even thought about fiber optic until I had to get new head lights for my Tamiya Pershing and they sent the new fiber optic kit as a replacement.