To note, the +/- 1k DPS listing for T14N gear that NonMagical linked from EJ based on different openers is DPS over the course of the fight, not DPS in the opening 5-10 GCDs. Anyone who cares about the last "up to" 1,000 DPS should really sim for themselves each opening sequence to see how different it is for them (between applying rupture and SnD first). It is true that this, in 120k+ environments, with an expected variance of ~300 DPS between MOST of the opening options, is VERY SMALL. If you're interested enough to ask, you might find it worth studying up on - and simming for yourself.
As NonMagical pointed out, what WILL hold true, is that you should play the opener you're able to perform ideally. I don't see swapping SnD vs. Rupture as a "first button" to be something that would change my comfort value with openers, but if it is, do what you do best. Personal performance > ideal button order, just like it was for combat to go ruptureless (when it wasn't a DPS increase to drop it on paper).
Verain: totally forgot that, never notice it since I'm usually saving vanish for emergencies and in the opening of the fight it's just not noticeable at all -.- (but then I don't play my rogue at a competitive level anymore, and primarily follow the theory).