Gradual means just that, gradual. One must consider the height of the locomotives under features such as the cow catcher so as to not cause any mishaps or accidents.
If she is so close in tolerance, I would shallow the grade as much as possible. In other words, take the track out even further and let her have more room to negotiate up the grade. I once had this problem, but with a diesel engine. My solution? Well, lets just say for the record, I doubt many would shave the plow up a few specs so she can run the track smoothly, but hey, it worked and actually the plow looked great as well.
PS I am not suggesting you do this to your loco's cow catcher.
Pete