My vote goes to 3 - two 100% is very rare and very good. You have twice the chance of landing a SSR that matches your eidos in future, and you'll make friends very easily. Both thunder and light are also very strong elements. Lack of SR isn't a big issue since you get two SR mtix - one from login and one from panel missions. If you decide to main thunder, one from story as well.
I would recommend playing through the story to get more jewels and see if your new rolls give you any thunder or light SSR before spending your SR mtix.