Nice recording - don't drive yourself too nuts. The off-center sound is partially that your Right levels are just a little higher, but also that the right side was picked up slightly before the left. The time shift doesn't look consistent... maybe the mics were off-center to the PA, but well-centered with regard to the stage (drums, bass, etc)? About 1.5dB more on the left plus a very short delay on the right seems to help, but I know not to trust my ears 100% for balance because one is more sensitive than the other.
- Jason