1: I don't think there's a specific page for this. At least not that I know of. The order of operations should be:
Intimidate > Evasion > Parry > Shadows > Counter > Shield Block.
2: You can expect to see around a 1% change in block rate for every 5 shield skill difference. Or to be more precise skill * 0.215. This value may vary slightly between different skill ranges and shield types, but this number has proved fairly accurate in most of the comparison's I've done.
Keep in mind that the base block rate is what the rate will be when player shield skill and monster combat skill are equal. And you are never going to be equal with any monster in ilvl content. So that base will be reduced.
Also the base block rate for a size 3 shield should be 45%. Not sure where you're getting that 55%.
As for what your actual block rate will be, I may be able to dig up some numbers later, but I wanted to get the basic answer out sooner than that would take.
2.5: Reprisal. A couple of things to consider here.
Firstly, Reprisal interacts with block+ is a way that is not favorable to the player. Reprisal is applied to the current block rate before block+ gear. So the block+ doesn't get modified by reprisal.
block rate = (Base*reprisal)+ block+
This sucks.
Next up, some corrected values. since the correct base for a size 3 shield is 45%, against a mob with matching skill we would do
45*1.5=67.5 + 20 = 87.5%
Or at least, it would have been. if it weren't for our next subject.
Block rate caps. Block rate hard caps at 100%, but that's not the only cap in play. There's another cap based purely on the players shield skill. And this cap also limits gains from block+ gear and reprisal. It's the reason why Priwen can't hit 100% block rate even with reprisal up.
So it's very, very, unlikely that BST would actually hit that 87.5% block rate with reprisal up with the shield skill it has.
I don't have a formula for the cap atm, though I may be able to infer something from some of my existing data. I'll try to come back to this in another post along with the expected block rates.
3: Block dmg reduction.
Adapa is a size 3 shield, so 50% dmg reduction base. Then the def on the shield /2 so 31.5. I've always floored this to 31. FFXI tends to floor things,. and well, good luck actually being able to detect a 0.5% difference in any tests. And BST has no shield def bonus traits so we can skip that.
So 50%+31. 81% dmg reduction on block. PDT would be applied to the remainder. So you be taking 9.5% of the original dmg, or reducing dmg taken by 90.5%.
I also feel the need to note that not all physical attacks are shield blockable. Needles and throatstab type attacks are physical and can be mitigated by PDT, but they can't be shield blocked. Further you can't block ranged attacks, which is incredibly stupid. And why EES still tends to hurt a bit.
I feel like since this post didn't go into the actual block rate value you'd have vs any reasonable ilvl content it may give an overly optimistic idea of what BST's block rate would be like.
Something to consider before I get into a full block rate analysis.
BST shield skill. 428. PLD shield skill with Aegis 440. Actually pretty similar huh?
Now have you ever seen what PLD's say about Aegis' block rate now days? It's garbage. Floored at 5% on like 132 mobs iirc. There's still Adapa's block+ and the PLD vs BST skill gap to consider, but I just wanted to say not to get your hopes up too much.
If you have a specific mob level or range of levels you're curious about, it would be useful to know that so I can try to figure block rates for the content you're actually interested in rather than a random example.