I’ve never been able to find this out. And I don’t own two lights I can directly compare with these emitter setups.
Say for example you have a Qlite Convoy C8 with a de-domed XM-L2 U2-1A vs a domed XP-G2 also with a Qlite in a C8. Both SMO reflectors and both running 25R’s.
I can not say specifically in a c8, but with a reflector such as the HD2010 for example, the XPG2 will have more KCDS but the beam of light will be narrower.
With xml2 the spot will be bigger and throw something less than xpg2.
I have a dedomed xp-g2 in an UniqueFire uf-t20 at 3.6A. My buddy has the same light with dedomed xm-l t6 at 4A. My throws visual more. We think the difference is at 100-200 meters. So i can say the dedomed xp-g2 has a lot more throw.
Someone has made a wonderful thread with different emitters and de-deomed version in Convoy C8 with lot of beamshots and lumens/lux numbers but I can’t find it…
edit : found it ! 2014 Project Build- Cree Trifecta *Bucket's C8/Cu data in spreadsheet* Seem like the dedome XM-L2 is far better
I kind of feel it depends on the diameter of your reflector. The gain in throw from dedomed xpg2 will be smaller and smaller when the diameter of reflector goes bigger. Of course they are both driven hard.
In another word, go with dedomed XPG2 if you have a small reflector light; go with dedomed XML2 if you have a larger reflector light say larger than HD2010. Just my thoughts though.
I've modded a Convoy L2/clone with both a domed XP-G2 and de-domed XM-L2. They are also both driven at around 5A. The XM-L2 wins out because its brightness simply pushes the beam further than the XP-G2.
I'm not sure if the same theory applies to a light with a smaller reflector such as the C8.