Make sure you put the planets at the front of the helmet, and the stars at the back. That way from the front you look like you're from out of space, and from the back you'll look like a shooting star!!
I, too, own a black Smith Maze and I ended up putting on a normal black oakley diecut to blend in with the original color of the helmet. Other than that, any diecut or sticker will be fine with the helmet. I mean it's a typical black helmet, you can put whatever sticker you want on it and if it's black, then consider it "camouflaged" into the helmet design.