Replying to Painters! I need your advice!

I want to paint a helmet...I was thinking I wanted it to say Hungry Sloth in a gradient.

So naturally I'd make a gradient, then put a stencil of the letters on top then spray paint the whole thing black or something

my question is...how do I make a solid gradient with paint?

also, I was thinking of doing a vanilla sky looking graphic. Any tips??

hungry sloth thanks you