Just to clarify, as a PA working on a texture set for G2F I learned this the hard way. Genesis 2 Female has her own uv set, but also comes with V5 uv’s so that she can use V5 textures. So, with the base female you actually get two uv sets. Then, of course, buying V6, Gia, or Girl 6 gives you 3 more uv sets. Teen Josie actually is now set to use the Base Female uv’s, but because she was briefly mapped for V6 uvs she does come with V6 uvs. Then, there is MallenLane’s V4 to Genesis 2 addon, which makes the V4 uvs available to Genesis 2 Female. In all, at this date, there are 6 uv sets that work with Genesis 2 Female: Base Female, V4, V5, V6, Gia, and Girl 6.
Your best bet, if creating eye textures that can be used by anyone that is using Genesis 2 Female, is to use the Base Female uvs or Victoria 5 uvs. This way you can reach the most people, not requiring them to purchase any addons or character sets.