DNS, will these provide additional range beyond the built in illuminator on the Photon RT S?
Yes, with better illumination. They have a bright spot and then splash (less well lit donut around the bright center). On an open field, they are great. If you get into clutter like high weeds or branches, the reflected light can be a bit much. The way around that is a laser illuminator, but they are much more expensive.
I was leaning toward the evolva but donít like the battery type. Is one preferable over the other?
Don't like 18650 batteries? That is a shame. They rock, last much longer than CR123s and you can recharge them.
I like the T20 Evolva myself. The streamlight takes CR123s and eats them, IIRC.
Note that the 850 will have a dull glow but the greatest illumination capability. If you find the 940 versions, they will have less or no glow, but will have a diminished range for the same type of light and power. So digital NV does not like 940 nm IR light. Not sure why, but apparently it is out of speck for it. I don't know well is plays with the Photon or Digisight.