My costume was very similar. I used 5m strips divided into 5 one meter strips, connected with data, clock, and ground and with separate power for each meter. 5 battery packs with 4 1.2v Eneloop batteries did the trick, and the lights lasted all night long. My LEDs were under a diffusing 2mm acrylic panel shaped into armor. Woot!
So much fun, to glow for halloween.