I guess you can’t go wrong with those materials you are indicating!
I don’t have any quad spacer but if kiriba-ru did a specific one for that light and you managed to sort the right MCPCB, great, you’re in the right way!
As for the driver thickness, not having the light I can’t be sure if that is the most adequate thickness. Maybe checking the original driver thickness in this thread can help you to chose the best one.
Or you can check this thread where longuylander built a quad version too.
About the LEDs, you’ll get a good neutral white beam with the 5000K XP-L HI.
Being a clicky switch, you can’t choose a driver with Anduril, as it Anduril is made for e-switch lights.
Please note that Crescendo doesn’t act like Anduril. In Crescendo, you click ON and it immediately ramps, while in Anduril, you need to press&hold to ramp. Check if that is the UI you want before ordering the driver.
Hope this helps in some way!