Screen print

I'm not sure how the colours I want to use for my screen prints will work, I want to use a very dark blue and very light blue and a middle blue. I am not sure that overlaying the light and middle will make a blue dark enough to work. I want to know If I can print the dark blue first then print light blue over it to make the middle blue. I don't have experience with this process. I have screen printed clothing quite a few times but not using overlay. I need to try out some other colour combinations as a backup in case I can't get the tones I want. The designs I have made are shape based and are quite simple. I think the strengths of my illustrations are the composition, textures and colours. I don't want to use half tones as that will compromise the structure of the shapes that make up the image. I don't want to have to make do with colours that aren't close to the balance I have made digitally, if I cannot make these colours through screen print I would rather change the colours entirely than compromise.