The thing about WW-II combat, at least for me, is getting a good balance between a plane that really looks like the full size one. That means it has to have key features, like high or low or mid wing, dihedral, and the general balance between the nose length, the tail length, and the bulk of the fuselage. For example, a P-51 has a relatively long nose and the whole stabilizer has to be in front of the rudder post, or it looks weird. The other thing is almost all the WW-II planes had pretty steep wing tapers(tip ~50% of the root) and small wings. The Hellcat is a bit of an exception. It had about 30% more wing area than the Corsair, which used the same engine.
The usual procedure is to figure the wing area you want. Scale the wing at ~1.3-1/4 in./ft. Do the same for the tail. Scale the fuselage at 1 in./ft. It's all relative. Then play around with the wing placement, the cockpit placement, an the length of the tail to make it look right.