The rating gap is the gap a top rater has over the second rated runner. This stat only applies to the top rated runner in a race.
Rating percentage is the percentage factor of a top rater's RZ Rating, compared to the rest of the field combined.
For example, if Anamoe is rated 200, and the rest of the field combined totals 200, the percentage would be 100%. This stat only applies to the top rated runner in a race.