I can't give you a scientific answer but I can tell you my experience with motor substitution. I have a low wing monoplane with a 60" symmetrical wing, about the first step up from a high wing trainer. I started with the recommended 0.46 two stroke OS LA engine. The plane flew ok if you just wanted to fly around but it didn't have enough power for vertical manuevers like humpty bumps and big loops. I put in an OS 72 4 stroke and the plane is now a lot of fun to fly. The bigger prop pulls the plane well on vertical lines giving me more room and time to do stuff like humpty-bumps. Loops can now be much larger. The engine is heavier but I had to put in nose weight anyway when I had the lighter two stroke on it. With the tricycle landing gear, the 12 inch prop has about an inch clearance to the runway. I used to run a 10 inch prop with the old engine.