MAX7221 Led driver discussion (again)

Using Arduino General Electronics
2
  1. You have to follow the matrix setup. How you arrange the LEDs on the ends of wires after making the matrix connection is up to you.
  2. There are lots of LED strips that you can send commands down the line to. "Close together" is your call.
  3. MAX7221 takes care of driving the LEDs, you only supply 5V to it. You are only writing data into a register that represents the 8 LEDs. There are some equations in the data sheet that tell you how much power the MAX7221 will drawing.

You are going into it too much.Select Iset resistor for a lower current per LED, if not bright enough with intensity set at Full, then raise it up some.