I was thinking for "lamping" with rifle....100m is probably more than I would ever need. I imagine the diffuser (that you siggested above) would really reduce the throw?
Mornin' Red. I did a night bimble with my dog and 11 year old last night. Specifically I wanted to see what I could get from the red filter. I found that if you need a bit more "enlightenment" the red filter was able to show up the uneven ground or badly maintained styles when we needed it without compromising our eyesight as soon as we turned it off. With white light there is a period where you suffer from night blindness while your pupils re-dilate.
To our delight we found that all our critters stayed put and didn't bolt. As a result we saw 3 seperate badgers and possibly an otter (will go back today to look for spoor and spraint) In the past I have seen tawnies without them getting stressed. As soon as you took the red filter off, they spooked and legged it even if you have the animal in the periphery throw outside the hotspot.
For lamping purposes I would probably only use the TK15 S2 on full power while using the red filter. 25 yards: brilliant, eye shine back and full, detailed body outline. 50 yards: Just eye shine back (technical term) only and it gets tricky to id what animal you may be shooting. You would have to rely on other clues or just not take the shot in the first place if you aren't certain. 100 yards: Personally I would struggle to take a shot at this distance with the red filter.
You could of course just use the flashlight without a filter and as the specs show, you get over 250 yards.
What say you? Have I helped? Let me know if I can help out more.............hc