It is more situational and I haven't yet put it through proper testing, but I'll be using VV, Smiting Blow, and Strong Arm for SAM/RNG, emphasis on the /rng. Unless you know of a better setup for Refulgent Arrow that you'd like to submit for further testing I think these work best in this situation.

Any other time, Atma of the Apocalypse Triple Attack is nice, because you practically WS every other attack round on a good GK and not a Soboro. auto RRIII is always nice too.
Voracious Violet is a nice one because of the STR +50, Double Attack +5%, and Regain +2. Self-Explanitory
Raised Ruin isn't quite as significant to Samurai because of our lack of Crit WS, but the amount of crits over time and the damage increase certainly helps. Wouldn't recommend though for events and NMs when you are on the back line and running in for WS.
Smiting Blow has TP bonus superior, as well as WS accuracy. This is something you absolutely should be using when not regularly TPing on the NM and running in to WS.

So yes, pretty much what Gunit said.