Lately I've noticed that I can free up cards for the Damage Diagram, Shields Diagram, and Pass cards in each 55-card deck by making the secondary configuration of each Titan a weapon-swap with another Titan. So instead of Titan decks carrying 12 weapon cards each, they would have 6 each for a complete set of 12 together. In some cases, however, the weapon swaps aren't quite so easily straight forward. For example, Tethys primary to Styxx secondary.
With Styxx sporting a Gun Battery 2 (right hand gun battery card) and Tethys with a Gun Battery 1 (left hand battery card), and both a Claw 1 (left hand claw card), it means that I would need to either use the 55th card slot in each deck to carry an extra weapon card, or I would need to swap Tethys' gun battery and macro laser. I mean, I could swap Styxx's weapons, but that's a good configuration.
Swapping Tethys' medium and long-ranged weapon would create something very like Rhea's primary configuration, with a left-shoulder laser and a right-handed gun. Certainly Tethys would still have a capacitor instead of a 5th extra armour, and jump jets where Rhea has thrusters, but it seems kind of same-y, or at least not showcasing the difference the placement can make.
I think the clincher might be that both the hand and the claw weapons can grapple an opponent across into their left or right hand quadrants. This is most useful for opening up a target to stab with the laser, I think, but also for slamming them into a sufficiently large block of buildings. While the macro gun is good for the occasional snap-shot, the gun battery requires crew operation to get the most out of it. Additionally, Tethys' secondary configuration already carries a laser blade in its left arm.
Tempo-wise, Tethys would need to spend three cards to grab with the claw, and then at least three more to shoot with the macro laser, possibly five to operate the weapon with senior crew (adherent, master). That would also be a chain of three actions, possibly four if a capacitor is used to regenerate the cards spent on activating the claw to fire the macro laser. Five cards for a crew-operated attack in two actions might actually be best, as a 5-cog attack with a laser is going to amputate something even under two shield tokens. Having that on both sides of the Titan might be best, with the gun battery backing up the claw at range. A macro gun would do a 5-cog attack in two actions (operate, attack), for four cards, but it would take five cards and three actions (operate, operate, attack) for a hand to do that. I think there's an edge there, removing a part of the enemy before they act with it.
So if I go the other way and use the 55th card for a Gun Battery 2 to make the conversion to secondary configurations workable, then that suggests I could use the 55th card in the other deck to do something similar. I'm leaning towards a reference card illustrating the incoming and outgoing arcs though.