Bill, at the 1st mention of depleting the turrets of firepower - i was reluctant as well.
Despite some play tests with the Aurora Gunship shoved an average fire support Dropship will obliterate an Atlas on a single salvo.
And where the drop ship weapons to stay at the endorsed weapons level, this Vanir one, being an Sub-capital weapons wielder, would single-handedly obliterate even Dropships, as it's build - intention was to threaten even Warships?
TL;DR: "hope ends here" on any map.
Would You even bother to just consider the ships canon arsenal?
Not only did I decide to give up on it's sub-capital part of it (The Stingray and Piranha missiles will be off-lined), and am about to "excuse" the 5 twin HAG40 turrets for the above reason...
You ("et tu filli?") ask me to turn the gem of the CGB fleet (equiv of WW2 Fletcher class destroyer) into an hot-dog-kiosk?
Why not just model an Papa Smurfs mushroom house instead?
And we all pretend we play Mario Bros?
But to be any remnant of CGB it has to have it's array of "LPL" (will be actually LBL "pretending to be LPL") and at least some of the twin ATM12 turrets?
Having in mind all above, note the turrets in question here are the new- non official ones, I can't see a way but to have them an fraction of their inherent firepower?
So an triple "LPL" turret could have 1/6th of it's 3xLPL firepower = 1/2 LBL.
Likewise the twin ATM12 would yield about ATM4 of destruction per turret.
This is still quite a firepower to bear, but could be an start for an actual play test?
Note: Current Calliope turrets don't use their missiles at all against any targets.