Walt175,
With the flasher/dimmer cap and a 3.5 AH Aero NiMH battery, the SL60 (SL-20X running 1160 lamp) is a really neat light. Unique amoung incandescents in its class for the range over which it can be dimmed, from a dozen or so lumens back on up to 450 lumens in a continuously variable arc. Very cool. When I owned an SL60 with the flasher/dimmer cap, I would start out walking with it rather dim. Like beat-up, abused 2D maglite kind of dim. Then only later would I power up. Kind of a stealth light in a way.
Plus the 1940 with MOP finish can yield a very nice SureFire-like beam when the 1160 ring-potted lamp is positioned just right, which isn't hard to do or anything. The ring-potted lamp is just adjusted once, then locked down with set-screw. After this it will not move, even if you drop the light. Plus, it is completely heat resistant. Extended running is no problem. No plastic socket to melt.
The downside, of course, is the larger size of the SL-20X (or 35X) light when compared to a TigerLight or SF M6. The upsides are the flasher/dimmer cap, and a switch that is easy to find (compared to a TL) and easy to activate with gloves--although the SF M6 has these upsides as well. Plus the 20X is a fairly reasonably priced light.
Personally, I prefer the TigerLight if cost is an object, or the SF M6 is cost is no object, but there are a number of good reasons to go for the SL-20X, particularly if your department issues them or something like that. With the 1160 lamp it becomes quite a viable duty light in my opinion, as long as the battery pack is up to the higher current draw. New stock packs seem to handle it fine, and the Aero NiMH 3.5 AH packs handle it very well indeed, but older stock packs are sometimes not up to the task.
Fair warning: I won't ever be mass producing these kits! I'm a small time modder and have no desire for a commercial exposure. Keep this a relative secret, please! I won't take orders for 10 or 20 of these, for example! These are made by hand, by me, and take some amount of my time. On the other hand, if you have or get one of these kits, I intend to always provide replacement ring potted 1160 lamps for you. I will continue to service all my mods that are in the field, in other words.