I have a pretty decent cloudsplitter set if I do say so myself. I'm only missing twilight body(using osode instead) and MAB rings(using STR+7 MND+5). Atmas aside, my BST/NIN cloudsplitter usually hovers around 900 in abyssea @100TP (Give or take a hundred).
-TP bonus atma: can boost damage up from 900 to 1200.
-Ultimate: boosts it a little better from 900 to 1350.
-Lion: boosts it comparably to TP bonus from 900 to 1170 + adds triple attack and a damage taken reduction.
I can get cloudsplitter up to around 1600 going RR + Ultimate + Lion
I 2000-3200 regularly with rampage in abyssea with RR+VV alone. Adding in Sang.Scythe, I've had rampage break 4000 on more than one occasion.
I have, though, considered making the TP bonus+100 axe now that I know it can be used in the off hand. With that axe, using RR/Ultimate/Lion, I assume I can get Cloudsplitter to a consistant 2100 damage at 100 TP. Thats still not gonna beat rampage, but its nice to be able to get it that much closer..
Still, others in my group went H2H, Sword, Katana, Bow, Etc. I envy their 4k CDCs, 5k Blade:Hi's, 7k Victory Smites, and 9k Jishnu's Radiances. Picked axe cause I love BST. It was a trap XD