Inside Abyssea, I know I've broken 6k, but I can't remember on what. 4-5000 on Piercing-neutral targets isn't that uncommon.

Outside Abyssea, 2700ish is my max (for the one session I looked at) against piercing-neutral targets. ~2100ish isn't uncommon when Striking Flourish crits. I did 2200 damage to Jailer of Temperance, for instance.

I have never actually stacked Striking and Building Flourish. Aftermath and Enhances Samba AF3+2 bonus at least can't proc on the main swing of Rudra's Storm.