Many people have fallen for the "beef it up because it looks flimsy" fallacy. In fact, the plane is quite delicate and flimsy, but it doesn't need to be built like a brick house. It only weighs 7oz, and is meant to fly indoors or in light breezes. Beef it up in one place, and it will break somewhere else on a hard landing. By the time you beef everything up, it's too heavy.

The final choice of plane comes down to your preferences. It sounds like you're leaning toward the T-Hawk, which isn't a bad choice at all.

I know you said don't recommend the Slow Stick, but I'm going to because I believe you overlooked some factors: Yes, it flies like the Tiger Moth, but it's also larger and heavier, and will fly in wind like the T-Hawk. It's also much tougher than the Tiger Moth, and frankly, I think it's better-looking.