ss or lidless

Then it depends on your build and your style.
Whitstan's Guard requires lower strength and less dex to max Blocking.

Lidless has FCR and Skill points, it depends on whether or not you need those FCR for you to hit the next BP. However, it will require a lot of dex to max blocking with it, so most would go for no blocking sorc. (And not avoid getting hit.)

Stormshield, well, highest str, relatively high dex to wield and max block with, but the Lightning resist and DR say it all...