The guaranteed victories in billiards and tennis were officially etched on Saturday but the Philippines anxiously stared at breaking the 50-gold medal barrier and a potential fourth-place finish in the 31st Southeast Asian Games that winds down to its last day of active competitions. Rubilen Amit and Carlo Biado pocketed the 10-ball gold medals and Ruben Gonzales finally won that elusive mint in partnership with Treat Huey in tennis’s men’s doubles that hiked Team Philippines’ gold haul to 43 as of midday Saturday. Rubilen Amit, a native of Mandaue City and now a Taguig City resident, beat com…