Do you need plumbers putty to install a sink drain?
A plumber must not be applied if the countertop is granite or full of loopholes. If you seal the sink properly it will be impossible for water to escape. The plumber’s putty must always be applied at the bottom of the sink and the sink must be placed with all the pressure on the countertop.
How tight should a sink strainer be?
If installed correctly, the putty should be barely visible (1/32 “ or so”). As you tighten the nut, the putty should be forced out of the gap insuring a good seal. Remove the excess with your finger. If sufficiently tight, you should not be able to move the strainer within the sink hole.