Here's some of my thoughts on this whole thing.
I got in an argument with a taru THF/NIN in west altep yesterday about whether or not it was more worthwhile to separate Sneak and Trick or if it was best to just stack them and ensure reliable damage and hate control. IMO, a THF is gimping his party if he's not contributing to the tank's hate dump and also if he or she passes on a chance to function as a pure Damage Dealer for the party as well. Li'l dude ended up leaving my pt. Anywho, I believe Fuidama should be stacked as often as possible until you have Assassin at 60, but even then you'll still want to stack Fuidama for initial hate dump, and always with a weaponskill. If you or your trick partner don't have TP and have at least until your Fuidama timer recasts, past 60 you can Sneak Attack with a normal hit and then run behind the tank and get the same damage with Trick Attack.
When to Fuidama > VB: I don't use this for initial hate dump, because it more often than not leads to a delay in scoring first hit behind tank and causes wandering problems. I always trigger Fuidama macro just before I let loose with /ra to pull or when the puller announces the pull. Then when the pre-voke goes off, I go to first person mode, target and lock the mob, run behind it about four character lengths behind, wait for Pld or Nin to align, then engage the mob and run up on it behind the tank for first hate dump. This method operates ridiculously fast, and usually Fuidama is recharged and ready to go within ten seconds after the tank has taken Fuidama and expounded upon it with their default hate control routine, and therefore the resulting Fuidama > Viper bite finisher on the skillchain will end the mob's existance once the SC and the MB finisher connect.
Good voke partners and SATA SC partners: Samurai have Third Eye, which gives them a free hit if they get first voke or if it charges midfight will help them if they draw hate with a renkei combo. Tachi: Enpi > Viper Bite = Distortion, Blizzaga/Water II/Blizzard II magic burst.
Dragoon: Double Thrust > Viper Bite > Distortion yadda yadda. Dragoons past level 50 are the best midfight SATA skillchain partners in the game, setup first hate dump on tank, swing behind DRG, execute Fuidama enhanced skillchain for big damage, DRG uses Super Jump which deletes their Enmity value accrued during the fight.
NIN/WAR or WAR/NIN: These guys operate about the same in the partner role, problem is finding a NIN/WAR that's willing to let another tank be main tank. Usually you'll proly find a WAR/NIN as the vokebuddy/SATA partner more than the NIN who is likely either main tank or not in your party at all. Either way Utsusemi helps them survive the initial voke and also if they end up grabbing hate post SATA. Not really sure about what War or Nin ws contribute to renkei with a Dagger finisher.
Also, I have 1.5 waits in my SATA > Viper Bite macro and it's never failed, I trigger the macro when the SC buddy auras when readying starter and the three second timer always lands a Renkei when mine goes off. In fact my 1 second timer on my normal SATA macro without Viper Bite fails more than the 1.5 second timer on my other one, considering raising the non-WS SATA macro to 1.5 as well.
Mang, Hobbit Hunter level 50
Infares, Man Burglar level 17
Dilf, Dwarf Minstrel level 18
Freshly, Man Champion level 17
Cofounder of Solidarity kinship