Unlike my friend Random User 'above', I never liked a long leader for tight work and tied one based on a formula given to C.W. 'Bill' O'Connor by George Harvey long ago and passed to me by Bill. I don't remember it perfectly but the below lengths are close.
20" of .019
16" of .017
14" of .013
14" of .010
16" of .008
If you are knotting your own leaders this gives you roughly a 6'6" leader that will turn well with standard flies used on small brooks. For dying a fly line see this thread; Dying a Fly Line;
A bright yellow line will make a good olive when dyes of brown & green are blended. The yellow will go to brown pretty well also. White lines will be the easiest but all lines can be muted for the purpose of better camouflaging them.