If you're looking for an airplane to overpower, the Lazy Tiger is the wrong one to buy. A .30 4stroke would be perfect for this one. Don't read too much into the horsepower figures. 2strokes make all kinds of HP at high RPM - not quite in with the character of this "slow flyer".

Any of the .30 4stroke from Magnum, OS or Saito should work very well. They can all swing big props, normally meant for .40 2strokes, and make good torque at lower RPMs. The OS FS40 is good too and at some 12 Oz. doesn't sound too heavy for a 3lbs plane.