Just feedback to the readers 
I bought 12v 6a 72w PSU. Now this 60m set runs with effect around 30 - 35 w (as original measured with smart plug).
So PSU was insufficient
I could be the beta tester also
I would like to offer testing help aswell.
Dual WS281x RGBW is only available from my fork as a self compiled binary.
Unfortunately I will not be providing pre-compiled binaries any more.
OK i will try to compile it myself. Are you planning to commit it to the main project?
Only if there is enough interest.
Where can I find your fork with dual chip RGBW support?
People have reported that FW1906 will work for dual WS2811 RGBW strips, although I haven’t tried it.
You’re right! FW1906 GRBCW works great. Color order GBR, Swap None. Auto-Calculate W of Brighter works great to get the benefit of the W channel for brighter white patio lights.