Now that's an idea (MC 40)
Instead of the Marauder Corvette and Broadside Corvette, use the MC40 and Acclamator-class ships. They would have weaker shields and slower movement than other ships in their class, being older ships and all; but their warhead launchers are reoptimized for long-range anti-ship missiles, and their turbolaser weapons can still leave a mark.
The MC40 Cruiser is an X-wing ship, and while the Acclamator is out of date, two things are in its favor; 1. It's main weapons are missile weapons, 2. The ship is direct canon from AOTC. I think that might work for the long-range attack demand.
GC Veteran (0.14-R6) "General Jafar"

