This is a very under powered racket in stock form. If you use poly, I would either use it as a cross with soft mains strings and also keep the tension low.
I string this racket for a friend and he is using bab 16g gut mains at 55 lbs with Kirschbaum spiky shark crosses at 50 lbs.
He likes the power from the gut and the poly cross adds a touch of control and spin.