Welcome to the board. Given your kids ages what triggered the sudden realization that something different might be needed?
As to gifted peers, the higher value would be in the chance that there may be kids like yours to make friends with similar interests and level of development. As to the context of ratios of NMSF, I'd think the most important academic influence would be on having enough students with a higher ability that teachers are more inclined to teach towards the top rather than the bottom or middle.
