As far as bombers go, I tend to not see the point beyond Ursa/Sekhmet(and maybe the Artemis, but bad gunpoints). If it's a cruiser, a wing or two of Erinyes or Hercs should suffice, especially if Trebs are employed to remove offending AA beams and flak. If it's bigger, it's probably a much nastier target to have to attack.
Ursa can carry Maxims(or Disruptors/Akhetons, in a pinch) in it's second(er, first) primary bank to avoid having to spend extra payload on Trebs, plus the triple 'gunrack' is incredibly tightly grouped compared to most fighters/bombers that are Maxim capable.
Kayser turret is good at scaring Shivans off, at least(can occasionally kill Manticores by itself, and I've had at least one occasion where I ended up simultaneously 'dogfighting' two of the leftover Basilisks in Slaying Ravana, one targeted and kept above me for the sake of the turret, and attacking the other with my 'anti-fighter' bank).
Helios/Harbinger is also always a bonus if available, and while the Boanerges is more effective at emptying its full payload of Helios, it definitely needs more competent escort.