I was wondering how the TE take on Rainbow Dash would turn out, since she already has a kaleidoscope of colours in her mane, even in Crystal Pony form. I think that you accomplished a different look to her mane and tail quite well. I assume it's from the tetrad colour technique you used on the other five?
Actually, these colors were taken straight from G1 Quackers.
I've been using the back card art for the TE Ponies to come up with the hair colors, and I saw that Quackers already had hair color near identical to those of the Rainbow Ponies. The only color I tweaked was the pink. I made it more of a red magenta to better evoke the red color of RD's regular mane.