I was using the BSS before it was cool
Also, the summonstone is where the archer is next to the boss fog. It's... not very fun to get to, and solaire likes to get distracted by the giants.

SO, small update: I had quite possibly the sloppiest 4-kings fight ever today, because I just wanted to get them over with. The murakumo was so not a good weapon for that boss as it made me get hit by every move out there. Coupled with the fact that I had to sacrifice my wolf ring for the covenant of artorias... it turned into a slapping contest where me and the kings just traded hits. Nonetheless, over 300 damage a hit allows a TON of room for error, and after downing about 15 flasks like some crude drunkard after finding out his truck got towed... I left depressed and annoyed but victorious all the same on my first attempt.
I'll have to do better in NG+