[member="Abigail Selonna"]
Honestly, as little or as much as you want. People started including a handful of LR and HRL weapons on all of their ships, so I made the Concordia. It's designed to engage an entire enemy formation by itself while other ships (specialized brawlers) keep the enemy away from it. Deck Cannons fire 1 shot Mass Driver and 1 shot Ion Cannon. There is a chance that the ion cannon will weaken the shields long enough for the mass driver round to punch through (similar to your 3-shot Javelin weapons), but it's not a guaranteed thing. Nor is it 100% official. It's just... a thing. You could just take heavy damage to shields, you could have the front half of your ships take heavy damage, you could divert power to forward shields, you could use maneuvering thrusters to get closer to the asteroids for cover, you could just "dive" (dip the nose down) and go full speed towards the asteroids to try and get out of the line of fire.
You've got a lot of options. But you've got 3,100 meters of Dreadnoughts with 100% Heavy Long Range weaponry firing at 2,000 meters of ships (and a handful of corvettes, but those aren't being fired at) with split HLR and close range weaponry. Tactically, you're out-numbered and out-gunned. And with the jamming, and the opposing ships moving (meaning they just became even harder to hit), you'd know you were in a bad spot.
Personally? I'd put all available power to forward shield, dip the prow down 45-80 degrees, and floor it into the asteroid field for cover. You might not maneuver well in there, but the Corvettes can cover your flank. And with as much forward facing firepower as you have, you'd be able to do some serious damage if you can manage to point-blank another heavy cruiser / light star destroyer. You'd likely take a hell of a beating in the process, but you'd survive, spend a few turns doing emergency repair while trying to limp closer to the rest of the Republic Fleet, and come back into the fight as a rear-line support ship. (since you'd be damaged)
I'd ask for some advice from Gir and Resh though. Coordinate with them about what they plan on doing and how you can best support that. You brought some great ships to the fight. Personally, I think they are the best of everything brought in on the Republic side of this fight. Had you not given Larraq a warning before shooting, you'd have probably have crippled his ship with that salvo.