I have one DIYC e1.31 DMX Bridge that runs 4 of the Pixel Extenders. Each Extender is one universe and each will drive 3 trees. There are 55 pixels per tree including the stars. That gives me 165 pixels per universe. I split them up by universe to keep the programming simple and I can separate the tree groups easily without worrying about data cable lengths.
The entire system is powered from one 24vdc 10 amp power supply.
I added a PDF with the wiring diagram this morning. there is also one with all the links to where I bought stuff.