hinges
I had to break my hinges on the first run model. On my second the entire bottom is already cut thru and the top doesnt bind too much. I would just break the bottom and be done with it.
On launch if you run a small prop its going to sink and roll/turn left no matter what you do. A 9 inch prop on a good engine will have little problem. A 7 inch prop is going to be hard to get airborne.
What engine you running?
Also make sure your CG is back far enough. youll never hold the nose up on a full tank if you are too far forward on takeoff.