Those will be fine. However they are only 30 LEDs per meter, so that is a spacing of 33mm between LEDs that reduces the number of LEDs per side you can get in your box. So a smaller strip of higher density LEDs might be better.
How long is the side of your box?
Four of these might be better NeoPixel Stick - 8 x 5050 RGB LED with Integrated Drivers | The Pi Hut