The 25 - 30% "rule" is very safe for almost any design, but many designs fly fine with the CG further back; 25 - 30% is very conservative and not necessarily good. It depends on the length of the tail moment, the proportion of stab to wing area, and wing chord. There is a well-known formula that I and others have given in other threads. If 37% works for a 1/4 scale Cub it will work for a Cub in any other scale. I do not find that forward CGs are easier to fly. As long as a plane is not unstable in pitch, having the CG farther back has a lot of advantages. It's a good thing to experiment with and see what you like.

Jim