I like the overbet on either the flop or the turn. Any rr in return, and I would fold. With 2 cold callers each step with your betting out, I think a good possiblity of a flush is present. Considering there wasnt any preflop raising.

Without the overbet in this hand, you dont quite no where you stand. With an overbet, you probably would only get 1 caller (if any), and this would help you in your future decisions on each street, since you would know exactly how much you could win or lose.