first off I'm a beginner. Tis is only my second kit. my first was a four star 60.I'm in the process of building a sig astro hog.Im building the tail dragger version.The kit said it can be flown with a 40-60 size two stroke engine.I already own a supertiger GS40. Is this engine sufficient for this plane or will it be underpowered. Im just a Sunday flyer. The kit also said to use a non knurled engine why?