One more link to an actual build, my Cometa build with the collar (560 kcd). The Cometa (or Jaxman Z1, of which the Cometa is a clone) aspheric lens flashlight comes closest to a low-trouble collar host as can be: its stock lens is of very good quality (the lettering on the side of the led is readable in the projection!) and has almost the ideal diameter/focal length ratio for this collar. Further, the small collar has the same diameter as rim of the pill so can be glued on top of it. The only fine adjustments needed is making a ring-spacer of very precise thickness (0.1mm accuracy) between pill and collar to focus the collar, and glue the collar in place whith its projection precisely centered on the led-die. But these adjustments are needed with every collar-build, unless the host is tailor-made for it.
