GREAT!!!!!!!!!!!!!
I agree with everyone who says variegated thread. Superior thread is the best Variegated thread for machine quilting, and I'm particularly pleased with Rainbow, because NO LINT.
Forget all you've heard about using RAYON. The Brothers Reps at the Sit And Sews I've been at say all the hype about Rayon being the best thread is just that - HYPE. Polyester is better - because it has much less lint, more colors and it's cheaper!
And I'd practice a lot on something else first. Lots of loops would look great to complement the angles in the blocks.
It's going to be a gorgeous quilt - it's already gorgeous!
As for color, there are a lot of variegated threads in the Rainbow line to choose from, and you can't make a mistake!