SH is easysauce for a prot paladin tank, so I'd say it's worth it. I'd use the trink if I had it.

As for libram, I use the block% libram, since my primary form of damage is via block. There's also the one that increases consecrate damage, which could also work.

I'd probably go for the Lightbringer since you have it already, and I judge wis pretty often. Holy shield charges fall off pretty quickly with the number of mobs you have, so I'll bet you'll be getting way more block out of the Lightbringer.