On the Adafruit NeoPixel Überguide it says:
On my tests I have 5 cm from Arduino's pin 6 to the first pixel data input of a 40 LEDs strip.Try to minimize the distance between the Arduino and first pixel.
But I need more distance on my final project, since two strips are running in opposite directions.
¿Is 1.5 m too much? I don't want tu burn a pixel making tests. Specially since some strips are out of stock.
:)