Okay, here is the real way to deal with the PITA silver knight archers.
Equip your most stable shield. Remove all of your armor. Keeping your weapon equipped is optional - read onward. If you're over 50% encumbrance, you'll definitely want to scale down; 25% or less is optional. It helps, but not as much as a good shield.
Run the fuck down the ramp.
Run the fuck past the gargoyles. Do not stop and fight them. If they hit you, keep running.
Run the fuck to the pillar. You can pause to regain stamina, but the gargoyles will throw lightning at you if you stay too long.
Run the fuck around the pillar to the ledge with the windows and the knight. Keep your shield up.
Stop running. Turn to the right and move toward the knight. Target him as soon as you can. This is important: When you block the giant arrow, you're pushed backward relative to the direction your character is facing, regardless of where the arrow came from. You want to keep your back to the wall ASAP, so target the knight ASAP. Before targeting, you can choose to block or roll. Also, the other knight shouldn't be shooting you anymore, but it can happen.
Right next to the knight now. Keep your shield up. Now you have two options:
1) Make the knight bounce until it falls. This can take some time and you might fall off yourself.
2) Parry the knight's attack and kill it. These guys are really easy to parry, but if you're not comfortable you'll just want to go with the first.
Knight is dead. Do not leap for victory. The other knight has a Soul of a Hero behind it. Your call on whether or not to get it. Do you even use those things?
Go to the balcony and do your touchdown dance. Then go through the first door on the left and flirt with Solaire.
Profit.
Spoiler: Fighting everything, especially directly, is the best way to die in Dark Souls.