It's a war of attrition to be honest, particularly in heavy combat, I find using the Scarab is still sometimes a good idea, since a Behemoth can't work whilst fighting, and it loses an awful lot of potential once you stuff one of those big modules into it.
Sometimes it's worth setting the Behe's up for combat centred only and drive around in a Scavenger Scarab, cleaning up afterwards, with a repair Scarab providing services to the main Behemoth group, the game always pick Korolev, but swap it to Kroker, since Korolev is more dangerous with the Longbow in my experience.
It's a pity you don't get more pitched battles with the Behe to be honest, but then Hostile Waters is one of those games you never want to end, and leaves you screaming for a sequel.