The TL/DR I can give you is what is going around in the community for prot wars. The first goal is to get your dodge/parry/block to total 75%. With those %'s when you hit Shield Block you will for 10secs not take a hit from a mob for full value(discount armor mitigation). To gemming, the common gem for at least now to get through heroics and early raids are.. BLUE: 60stm, Yellow: 20 mast, 30 STM, Red: 20 parry, 30 stm.
As to Hit/Expertise... having it is nice but alot of the entry gear has one or the other. Most people are using these stats to reforge into mastery to get their block % up. Personally, I just let this go down as far as I could comfortably maintain threat on single target.
The soft caps for these if your interested are 8% hit, and 26 Expertise. You'll not want more then that as the excess would be better spent or reforged into survivability stats.