I'll be honest, if you want a couple of c2 hit scan weapons, I'd go for long range rails every time. And for PvP duelling you'll usually want at least one of feedback cascade or super penetrator in your corner ... if you're going to fight all comers, ideally both.
However, if it's definitely to be pulse/burst, then personally I'd either go for two efficient plus phasing (added to the other two efficient you mention in the OP, that would stack to a lot of hurt against a shield tank with a thin hull) or I'd go for long range (for the lack of damage fall-off). You could put scramble spectrum on one of the long range, for anti-hull harassment.
Note that whatever you go for, corrosive adds +20 to the APV of any weapon striking hull, in addition to the flat +25% damage bonus. So if you work corrosive into your build, all your lasers will get +20 APV.
LOL, the ship kinda is the secret, though ... it all fits together, the speed, the ship, the defence, the loadout ... but it's the unusual choice of ship that is the starting point. There's one ship that does what I'm after, heh. If only it did everything else as well, though ...
I look forward to learning more of your own build when all the reveals are in!