Next time, you should try some addressable LEDs. Neopixels, aka WS2811/12/12B, let you set the colors of individual bulbs instead of the entire strand. They work great with ESP8266!
https://www.amazon.com/ALITOVE-WS2812B-Individually-Addressa... are perfectly cromulent LEDs and less expensive than Neopixels. Not as cheap as the RGB strips, but if you pick off more points for colour analysis, you could adjust them along the edges, if you really wanted to.
Nice work on the project!
https://blog.adafruit.com/2015/06/30/updated-neopixel-suppor...