The problem is that as the wing-loading goes up flying qualities diminish quite quickly. The airplane has to fly faster for the wing to generate sufficient lift necessary because of the higher weight. The stall speed of the airplane rises, and it becomes downright unmanageable at a certain point. If all you need it to do is go straight up then power-to-weight becomes an issue, but that's not realistic.

Have you thought about starting with a more conventional trainer? It'd give you valuable experience and insight that would increase your chances for success with your P-38.