No snail needed. Snail takes care of AIR, not fuel.
Turn the screw in gently until it stops and count the turns. After I get carbs set I screw them all in and write it down, then turn them back out to where they need to be.
That's what I recommend. Also make sure the screw(and spring, washer, and O-ring: don't lose anything!) and jet go back in the same cylinder/throat. It matters.