OK guys, here is the 4-Layer PCB at Oshpark; from MTN.
Parts kit. The parts needed are the same, except I can only recommend using Coilcraft XAL6060 inductors at these drive levels and there are 2x diodes instead of one. The second diode basically just heatsinks the first, but it works. The second input capacitor is optional. After reflow, fill the exposed copper on the FET's drain pad with solder for increased thermal conductivity and decreased electrical resistance.
Ordered.
Here are some pictures for those you looking to build your own. The regular (non-HP) version is pretty much the same, so you can use these to guide you with it as well.
Thanks once again Richard!
Wow that looks like a tough build!! 
Hey folks. RMM added a parts kit for the 4-layer board. Pretty excited about this little buck that could so I had to order.
Remember if you order the parts kit it isn’t an SOIC8 Attiny, so it’s a little harder to flash. I made the mistake of ordering the mcu bare
What would one’s “Ideal build” be with this driver? Host? LED? Battery config? Looking for some idea’s?
UF 1405. That light rocks with a good driver in it. 5A constant current until the two 26650s are dead.
Thanks Richard, sounds like a winner!! 
This driver is awesome in the 1405. I've been playing with one of RMM's four layer buck drivers set at five amps in a 1405 for a couple months now and the driver has held up flawlessly. The four layer MTN MAX combined with a dedomed XM-L2 in the 1405 lights up the treeline out back of my house at 500 yards easily. I'm guessing it will do twice that range but I haven't confirmed that. I've also put one of RMM's two layer MTN MAX drivers at 3.5 amps into a mini mag running triple XP-Ls. That was a cool little light.
SOLD! Got one on the way! :bigsmile: Tend to dig lights that ROCK!!! 8) Oh it should really ROCK with the XP-G2 S4 2B de-domed!!!
You should see about 480kcd out of a 1405 with an S4 2B at 5 amps. Ask me how I know.
That’s cool! I am waiting for my parts from Richard to arrive but I am going to push the dedomed S4 2B at “only” 4.5A for reliability concern. How much candela would you expect at 4.5A?
I don’t know, maybe 425-450kcd.
could you take some long distance beamshots of that white laser ??? I would love to see what this driver can do in a 1405!
I’m using a different, lesser quality 5A buck driver. I have yet to do one of the MTN-MAX drivers, but performance should be the same/similar.
I’m building my kit now. I think I’ve figured it out by process of elimination, but “CMAX” is the Buck IC bypass, right?
Correct. Make sure you get the thermal pad on the buck IC reflowed fully.
oh…
lol wish I had read this before I just soldered the thing into the pill