For this system, I don't worry about our fast and final success.If they have no PD ships, that's easy - we've already shown we can destroy 5 ships before they can close to beam range.
On the other hand, I wouldn't be so optimistic if we faced not one, with possibly not full magazine of anti-ship missiles, but 4 or 5 at the same time. If they were alone, I think our fleet would eventually defeat them, but we would still lose some ships.
I only mentioned using our current launchers because that means it could be implemented right now - we just need to design size-1 missile. This way, no need to retool a shipyard and refit a ship, losing 1-2-3 years before going back to clean Wolf 294. Of course, in the long-run, having ships designed with smaller more numerous launchers would be good.
(I won't tell you right now how many launchers my Precursor PDCs have, that'll be fun when we meet them)
EDIT: Thanks. Ok, then Khan is just a big warship, nothing too impressive actually. I've no idea if ammo ships would be that size, or bigger - on the other hand, I don't think a mostly supply-oriented ship would have size-6 missiles, which reinforces my feeling that Quift was right about it having already fought earlier.