What's the maximum gap between the steel and the concrete? I really can't get a sense of scale from the picture and I think that's what's causing part of my difficulty.
What might be possible is to set the steel straight, use it as a guide, and then cut a chamfer into the concrete to create a gap that looks uniform at the top and hides the variability that exists below it. Not exactly sure how I'd do that without staring at it a bit longer but that was the first thought that I had.