well i would say it depiends on the art. i check the gallary alot that being siad i would look at some of the other art in the gallery and see if yours would stick out. so if your changing art styls alot then it would be smart to see what is going on in the gallary to agian see if your pianting sticks out.
and i choose around eight or nine o,clock. mostly because at the end of the day alot of people dont have any thing they need to do.
if it is for likes or comments or even followers then try to find someone who relates to your art in the gallary and become friends with them.Because the followers who love your art natraly ar the ones that will coment and like the most....and how much your art is recinized by other people.
well i hoped that helped and thanks for trusting me! :)