I too have the polymer stocked GSR. Have been trying out a Burris Scout 2.75x20 and a small Bushnell TRS-25 thus far. I also have a conventional Leupold 2.5x20 that's on deck to try out with this rifle. If I go that route I'll likely just use the Ruger rings. If you don't have any compelling need for the back up sights, I'd stick to the Ruger rings for a conventional scope. The rifle already needs a slight cheek riser for me with any of the listed scopes mounted in the lowest rings and mounts available. The XS rail adds another 1/2" at least to the height above bore.
One other thing Doc, if you want to go with one of the 30mm Leupold scopes, Ruger will usually swap the unused supplied rings for a set of 30mm ones at no charge other than the cost of mailing your rings back to them. I've done this on both my GSR & 77/357 when I needed lower rings than the supplied ones.