Sorry no schematics here yet - will draw and add some hopefully in the next few days.
Two things to point out. First, we wired our matrices for power in a parallel circuit - meaning each matrices was wired for power from the source, rather than passing current from one matrix to the next. Second, we soldered a capacitor between the 5v and ground terminals on our DC power jack. According to the literature, this capacitor protect the LEDs from the initial onrush of current when we supply power.
1) We read the following guide several times https://learn.adafruit.com/adafruit-neopixel-uberguide/power
2) Soldered our capacitor between the + and - terminals of our DC power jack.
3) Soldered wires to the + and - terminals of aforementioned power jack.
4) Split both + and - wires three ways, soldered, and wrapped in electrical tape
5) Soldered a + and - wires to the 5v and ground pads on each NeoMatrix.