My first playthrough I underrated the very strong Pyro Buff in Blighttown. It's worth grabbing if you're coming in from that direction.
Speaking of...
What's your setup? I went full Glass Cannon vs Four Kings+ and ripped them apart. I optimized for fast roll/magic defense, but poise would have worked just as well. Then again my solution to everything PvE is massive overwhelming DPS.
Mugen Monkey is the best tool around when looking for what armor to use. Just throw your END and weapons in then you can sort armors by anything you want. I've played the game enough where I'm frequently already using a setup similar to what I discover. Mostly just played with armors that looked neat to me and a backup set when necessary to handle invaders more efficiently.