Well, it’s not expensive so I think you should try it 
I received my double A/R lens from cnqualitygoods today. I got 3 for $1.90 but expected, at that price, it would only be one. They came wrapped in about 10ft x 6in of bubble wrap. The packaging and shipping alone was worth more than what I paid. It took 12 days from when I paid which I think was pretty good.
http://www.cnqualitygoods.com/goods.php?id=1970
To those who tested and posted the resulting gains of A/R coating, thanks! 
xp-gs are definitely different animals to xm-ls, at this point though, having both xp-gs and xp-g2’s, I would strongly urge you to get a noctigon mounted xp-g2 from intloutdoor, couple it to a qlite driver with the fourth star soldered and enjoy one of the best flashlight builds you can find, if its staying domed, get a 4c tint or close, dedomed go for a 1a or 1c ish tint.
thank you but I have neither the tools nor the skills to make a modding :~ ….i want to buy a C8 stock with an XP-G!…if there was a drop-in with an XP-G2 to replace i can buy it 
I’ve only ever found a couple of xp-g c8’s on ebay tbh they are a rare beast indeed
I’m sure this is the reflector I used in a build.
http://www.fancyflashlights.com/goods.php?id=56
It had a very small hot spot.
I’ve got one here for my c8 build good to know it’ll probably do what I want it to do, just waiting on my fasttech order now foe the c8.
They sell a deeper reflector C8 at aliexpress http://www.aliexpress.com/item/Free-Shipping-1PC-UltraFire-C8-Deep-Longer-Reflector-CREE-XM-L-U3-LED-5M-1600LM-LED/839114841.html
Would be a very good small thrower with dedome XP-G2.
http://www.fasttech.com/products/1206303 has the 41x41mm reflector too. And a nasty nonstandard low profile aluminum thing where a pill should be, unfortunately. I don’t think the exxxxxxtra deep reflector works as well as the plain wide-base XRE reflector with a XML. Just buy a cheap, plain XRE C8 and replace the LED & driver. It’ll be less work and you’ll have a light that not only throws a nicer beam but also takes the standard C8 pills.
This one (http://www.fasttech.com/products/1206100) has an AL reflector despite what the specs say, and the bezel is stainless, not clear anodized aluminum like you'd expect from the pics.
Comfy - I posted a discussion question on that C8 light at FT about it's SS bezel - that's a great price. I paid $25 for a TMART C8 host just to get the SS bezel from it! Wound up it easily inter-changed with other C8 regular bezels. Deeper reflectors do nothing for me. I got a couple of C8 sized lights I bought for the deep reflector and the standard C8's throw better - it's all about width not depth. Deeper reflectors simply reduce the spill area, they don't seem to make the center beam any more intense. I'm speculating there's a minimum depth you need for the best throw, then after that, there is no more gain on throw
I appears that the short reflector bounces the light once to get it out the front but the longer one bounces it twice before it gets out. By looking straight into the half-OP type, you can clearly see the OP being reflected from the smooth area. The advantage is less spill and maybe more OTF but also more loss from the reflector.
Here’s one at a lower price and shows the half-OP. It doesn’t show a straight on view but I have one and it does reflect an OP image of the LED being reflected across the reflector to the outer smooth area before it appears straight out the front.
+1
I have the same thoughts based on my experience with a bunch of reflectors..
And believe me, I have tried some deep stuff, even in C8 sized diameter (C8 in the middle btw).
I actually prefer wide and short reflectors. Gives the best of both worlds in many cases, both spill and throw.
Interesting ! Of-course it should depend of the LED used and the quality of the reflector (% of light bounce-of).
There should exist a simple equation relating to the angle of the light emitting source and depth & width of the reflector for different beam pattern.
But are you sure that even with de-dome XP-2 (different light angle) the deeper reflector don’t increase the throw ?
I got 2 example lights of deep reflectors, a SupFire X5 (BLF group buy) and a TrustFire 168A (from FT), both deep reflectors and the center spot looks intense on a white wall but under real use and a light meter for throw, both are worse or no better than a C8.
Not sure about de-domed XP-E2 of course - these were with XML U3's compared to XML U3's in C8's.
Regardless of what reflector used, the XP will just be a narrower beam. The optimum shape for throw will be the same for both for a given size. Here’s a quick and dirty drawing.
ok, about deeper and wider reflectors (nothing different from aspheric lenses with different focal length by the way..), I'm sure it is explained more extensively elsewhere.
Take two reflectors of the same diameter (like these c8 reflectors), one is deeper than the other.
The deeper one will catch more light from the emitter and put it in the hotspot, but because the focal length is shorter, the hotspot is bigger.
The shallower one will catch less light from the emitter and put it in the hotspot, but because the focal length is longer, the hotspot is smaller.
So either your hotspot will have more light, but more spread out in a bigger hotspot, or your hotspot will have less light but more condensed. So which spot will be more intense (throw) I don't know (perhaps there is even an optimum reflector depth), but because two factors that have an opposite effect on throw change at the same time when you change the depth of the reflector the effect on throw will never be very big, as you already found out in practice.
as far as I can think of now, the emitter type/size is not a factor involved in this. A reflector that throws best with a xm-l will also be the best one for a dedomed xp-e, just get your focus correct.
You can’t increase the length without increasing the width or the optimum curvature will be changed and some light will be reflected in a different direction. Both have to be changed to maintain the beam’s direction at all points of reflection. It’s simple geometry.
Reflector quality matters.
This one from FT really cleaned up all the (horrible) artifacts and tightened the hotspot/corona on an 7.99 Aurabuy C8. The UF-V3 makes a nice beam profile in this reflector size as well.
Yep, that's the C8 reflector I like too. That shape/design is my preferred one for XML C8's - it's available a couple of other places too.
I didn’t have time to add this earlier but it shows how a larger diameter reflector produces a narrower beam.
