I'm toying with this idea for a while and I think I have something interesting to try out, but i'm not sure how effective it would be:

SSD + Onager (0/397/400)
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Command Prototype (220 + 61: 281)
+ General Romodi (20)
+ Damage Control Officer (5)
+ Emperor Palpatine (3)
+ Lira Wessex (2)
+ Gunnery Team (7)
+ Intensify Firepower! (6)
+ Take Evasive Action! (6)
+ Leading Shots (4)
+ Annihilator (8)
Onager-class Testbed (96 + 20: 116)
+ Hondo Ohnaka (2)
+ Veteran Gunners (5)
+ Auxiliary Shields Team (3)
+ Orbital Bombardment Particle Cannons (5)
+ Cataclysm (5)

The basic idea is to fire with Cataclysm through Annihilator, always granting the extra red die. And if anyone tries to sneak upon the Onager, then the SSD would get the extra red. Everything else is there to fix as many of those fickle red dice as possible and boost the survivability of the SSD. I'm slightly concerned about not having squadrons (Kallus instead of Paply could probably fix that). Other weak points are the slice weakness and the fact tha tI have to take the weakest variant of boh ships in order to fit into 400 points. I have several ideas for objectives, but probably Surprise Attack, VIP and Dangerous Territory would be the best.

I’d just worry about being out-deployed and letting an opponent with somewhat speedy ships kill the Onager after they stall to see where you put it.

Without the extra pieces for the cataclysm alpha strike it may not be worth bringing either hondo or cataclysm. Especially as people learn to watch for the trick.