I know there's already a few threads going for the Courui, but I thought I'd put this up as a quick reference that addresses the issues with the stock light.
The only components I have replaced are the stock wiring, as it's about as thick as a gnat's hair, & swapped out the MCPCB for an XP-G2 on a 32mm Noctigon. I also added a tail switch for lockout.
I started at the rear of the light by using 22 gauge silicone wire to upgrade the springs;
Then on the back of the board, removed the tiny stock wire & added an Omten switch, connected to each via by 18 gauge wire. A 13.5mm hole was also drilled in the cap to accommodate the boot;
Next was the pill assembly. The pill was turned over, sanded flat, drilled & tapped for the 32mm Noctigon, which was also lapped. Screw holes were countersunk to avoid interference with the reflector base.
I didn't bother with sanding the pill all the way down to remove the grind marks, as it's really not necessary - the copper board is doing the work here, & there's plenty of surface area where it mates to the pill top.
The underside of the reflector is completely flat, & 26mm wide, which is going to make things tricky to get it sitting low;
I figured the best way would be to make up some thin copper tabs, & get the wires away from the reflector. I also filed a small bevel on the base of the reflector for added clearance.
Here's the pill assembly ready to go, with the now de-domed XP-G2. I used an XM to XP centering ring, which was sanded down until it was flush with the LED base, then attached with a small wipe of super glue to prevent it from falling into the reflector.
The driver was then modified by replacing the R200 resistor with a direct bridge, & replacing the stock LED wires with 22 gauge. No need to replace the switch wiring.
I bench tested the driver at this stage, & measured just over 4 amps to the LED, using a single cell (25r) & long jumper cables & alligator clips. Installed in the light, the actual figure will be higher without the added resistance of the test leads.
I also added some solder blobs to the battery side of the driver negative ring, so as the battery tube presses up against it when installed;
Pill tightened down in the body & wired up;
Light is assembled & checked for operation. As some other members have noted, with the resistor bridged, there is always a small amount of power getting to the LED;
A bonus Moon mode :) With the tail cap switch installed, it is not an issue.
Performance;
I measured throw at 10 meters, & also took a back-to-back measurement with my stock K50v2.
K50v2 measured a calculated 871 meters.
Courui measured 1166 meters.
Not bad for an afternoon's work! :)
Beamshots;
A couple of quick mouse-overs between the Courui & K50v2 to show the difference in beam pattern. Distance is about 15 meters. (Mouse-over for K50v2)
The hot spot is small, but searingly bright. Longer distance shots would do it more justice.