You might think that a overcharged G5 multi will have similar damage to a AX multi but that's far from the truth. For me it feels like 1 big AX turret deals more damage to scouts than 3 gimballed G5 multis...
Got 4x AX multis and 3x G5 gimballed multis on my Challenger. Scouts go boom. Have tried thermal vent beams and frag cannons, but the multis work best for me.
2 Large AX Multis, 2 Med Gauses and 1 Overcharged 5/Corrosive Large MC on my Krait II. Did the test and 1 AX Multi does much more damage to scouts then the Overcharged Multi.