I tried to bypass this limitation by setting up targeting priorities per turret subsystem and then flagging equipped weapons with "huge" or "small only" flags. Unfortunately this didn't produce expected results.
As testbed I used GTC Fenris, including tbm's from mediavps.
$Subsystem: turret09a-01-main, 4, 10.0
$Alt Subsystem Name: Artillery
$Default PBanks: ( "Terran Artillery AP#Fenris" "Terran Artillery HE#Fenris" )
$Default SBanks: ( "" )
$Turret Direction Preference: 100
$Target Priority: ( "cruisers" "corvettes" "capitals" "super caps" "bombs" "weapons" "asteroids" "bombers" "fighters" "ships" )
$Flags: ( "check hull" "no subsystem targeting" "fire on target" "reset when idle" )
The AP version has "huge" flag while "HE" version has "small only". What happens is that the AP works as expected, but the HE aims, fires once, resets back to idle position, aims, fires once and resets back to idle position, rinse and repeat. mv_assets-shp.tbm includes $Turret Reset Delay: 1000.
Is this a bug or what?
Edit: Another problem. If I swap the AP and HE weapons around so that the PBank order is reversed, what happens is that the turret now uses the HE weapon to fire at large ships even if the weapons is flagged as "small only".
Edit 2: Adding $Turret Reset Delay: 10000 avoids the turret resetting itself, but again it seems to use the AP on small ships and rate of fire is severely hampered. Commenting out target priorities makes the turret use the AP weapon against small ships, even adding "capital+" in addition to "huge" doesn't change this.
Apparently using weapons that have different targeting priorities in same turret simply doesn't work. Is this fixable or should I just forget about this?