I honestly can't recall anything about the Samurai quests being difficult in any way, I suggest at least being well geared enough for it, as well as using role actions like Bloodbath and Second Wind on cooldown to keep alive, maybe pop a potion if its that bad, if you still need more health, make sure to use Third Eye followed by the proc'd health restore.

As for rotation, not much to say, just rotate it and use Midare Setsugaka when you have 3 Sen, make sure to apply Higanbana (1 Sen) as well.

Want to help more but I can't recall anything about them, for the lvl 60 quest I know I was easily around i270 since I had a BiS MNK back in HW.