What size tattoo needle should i be using?

If your doing a full color tattoo, meaning just one shade i usually use a round shader, if you want to do transaction from light to dark i use a flat mag. Sizes all depends on what your comfortable with, for a large piece or tribal i use a 25rmag and a 5rs for tighter space. for the tip i use the same liner to fill in. but just try and see what works best for you.

This is my advice I have 6 years of experience currently working as a tattoo artist. Some artist will agree or disagree with my advice.