Here are my goto builds:
For range, merc - left flak gat - right flare banshee. Left flak gat uses lesmok and right flare banshee is heavy clip. Spanner mallet buff charged merc. Heavy clip banshee extends effective range and lets you hit a specific target (hull) rather than half the shots missing (balloon). Both engies use regular at closer range. Artemis can be used in place of banshee, but banshee deals 50% higher dps. When necessary, the buff engi jumps to the flak and uses buff charged - the highest dps mid range ammo. Pre combat, buff engi buffs left engine, right, then top, and left engi loads flare with lesmok if necessary
For mid range, hades - left banshee gat - right flame flak/banshee. Left greased, right heatsink/greased, top buff greased. The idea is dps, and the gunner jumps to banshee or flame for close range. Captain brings lesmok to preload hades with if necessary
For close range, mine - left banshee mortar - right flare carro. Left greased, right incendiary, top mine gunner. Definitely not for the faint at heart, and made more difficult by the limited mortar arcs at close range
As a bonus, artemis - left banshee gat - right flare carro. Left greased, right heavy clip, top buff burst. This is very situational as it lacks killing power with the sole buffed artemis. It's best against junkers, which are vulnerable to disable and have low hull. Buffed aretemis wrecks component clusters, and the gat carro can each target components if necessary. As with the above mine loadout, the flare is a primary combat weapon
As captain I always bring extinguisher for the top gun. Standard tools are hydro, drogue, kero, and when not worried about balloon pops, I swap drogue for tar. Left engi brings extinguisher and right chem spray. Against heavy fire the left can bring chem, and chem is always mandatory on balloon. Buff engi always buffs left engine first, then right and top. While buffing an engine, the corresponding engi on that side repairs the main engine