I am missing the midium head, so here are the photos.
All photos are taken about 1 meter distance from the wall.
Kel-Lite 7D Large Head, with a Philips PR20 bulbs.
The best beam in my point of view.
Some PR20 bulbs have narrower filament so the beam is more rounded and focused. Good quality PR20 bulbs such as Philips PR20, GE PR20. Avoid CEC PR20 because they have wider filament.
Same as above, Kel-Lite D-cell Large Head.
It is actually a 2D Large Head, I put 6AA and a Maglite 7.2V Krypton bulb in it.
This is a Kel-Lite 1D with small head.
I do not have many D-cell small heads so am not sure if the reflector is original becasue it has beautiful and smooth beam pattern. I have two Kel-Lite 1D, and they all have this similar reflectors. I have another Kel-Lite 2D, but it comes with the C-cell like reflector.
This is a Kel-Lite 2C which already has a very good qualit Maglite 2-cell Xenon PR bulb in it...
For comparison is a Maglite 2C.
The same Maglite 2C
Surefire 6P with P60 lamp assembly.