We are looking into purchasing our 1st pontoon, thinking about 20 ft 2013 qwest 220 RLS with 90 hp, little worried about the horsepower and pulling a tube. Can a 90 Hp on 20 ft pontoon pull a tube at 20 mph with 5 to 6 people on board? Do I need to upgrade to 22 ft with a 115. The qwest is a...