I have a beautiful titanium BitZ light and was wondering if anyone has tried a slightly smaller o-ring to decrease the resistance of the twisting. i don't need this to be absolutely waterproof and am willing to sacrifice that for a smoother turn. It isn't the titanium threads-- without the o-ring it is very smooth. Suggestions anyone? I'm really needing a suggested size and don't have a way to properly measure the standard o-ring.