Your progression is in the key of G, which has a relative minor of E minor. To get started I would stick with playing in E minor pentatonic as that will sound great over that progression and is relatively easy to play.
Once you work past E minor pentatonic, at that point you can start to integrate your other minor pentatonics into the mix. In this scenario, you can use A minor and B minor. A minor and E minor will sound the best but try out B minor and see what you come up with.
Good luck! :D
Douglas Showalter