Hi, Yes get mastery on all your gear until you get unhittable. 30% damage reduction due to blocks while holy shield is active is boss.
So what do you need to get your mastery to.
Well, it goes like this. You need 102.4% avoidance to become unhittable. Meaning all attacks made on you result in either a block, parry, dodge, or miss. So how do you get there?
Add up the following
Block + Dodge + Parry + 15(Holy Shield) + 5(Everything has a 5% chance to miss another thing of equal level) = X
When X = 102.4 then you stop with the mastery because it is wasted after that.
So what is up with 102.4%? Why not just 100%? Like I said before everything has a 5% chance to miss anything else of equal level. Well bosses count as being 3 levels higher than you so you need a little more. that is where the additional 2.4% comes from.
On your question about hit and expertise. Absolutely get to your hit and expertise caps. We need 262.32 Hit and 26 Expertise.
On your question on choice of weapons. Either. The sword has decent stam on it and the higher weapon DPS might help you with threat. The Mace is a tanking weapon and is ultimately better for survivability but I wouldn't sweat it too much.
As far as spec goes I do something more like this:
I don't think anyone has really worked out the best spec. I like the self healing too but for serious threat you aren't going to want to use it instead of Shield of Righteousness but it might save your ass from time to time. You definitely want 3/3 Crusade though. 30% Damage on our main attacks should not be overlooked. Oh and your glyphs are terrible but I assume you know that. Looks like they are left over from a healing spec.
As far as rotation goes just interlace your other abilities between Crusader Strike or Hammer of the Righteous. Shield of Righteousness when you have 3 holy power. It is sometimes in your best interest to fish for a Sacred Duty proc on Judgement before you use your SoR. Meaning if you have 3 Holy Power and no Sacred Duty proc and your Judgment is about to become available it may be in your best interest to save the 3HP SoR till after you judge. The auto crits are key to out threating insane DPS.
I'm not going to go over the gemming and enchants for tanking. Those can be found on this site fairly easily. Just a note though with unhittable being so easily reached now it is making the Hodir Shoulder enchants better than the ones with 30 stam. You might consider it.