Ed,
Your Falcon looks like the Model Airplane News version. The rudder was too big, the fuselage too fat, the span was wrong, and the airfoil was wrong. Inspite of all that they flew well, but not as good as John's. The version that I kitted was the actual airplane, developed from John's actual templates, and is better yet.
Yes, it sounds like you needed nose weight. John's Falcon weighed in the high 50s and was certainly more than the old Fox should have handled, but he flew it effortlessly. He was a master of trim.
Looking back, the Fox .35 days were interesting. It was normal to have the lines slack a little going over the top of the wing over. Have no fear, it always came back out at the bottom. It was also normal to whip the airplane into the first loop of the clover, and add bias to the loops and squares in the wind. These were"tricks" that helped us then and now.
The Fox 2-4 run helped along with the proper fuel and some small mods to the engine. With the Fox we were behind the power curve, but we didn't really know it. This mistake was actually repeated when Lew McFarland flew the larger Shark with a .45. It wasn't until the ST .60 and the OS .46 engines appeared that we found that power vastly improved performance. It is now common to see a .60 in a Shark. Today, as you have discovered, you can put a LA .46 in the better of the Classic airplanes and they come to life! We now know how good many of these airplane actually are.
Tom N