Can someone please explain the SEE/ Thrawn/ Armorer technique

You want Armourer just faster than Thrawn, (don't forget to factor in SEE's lead speed bonus for Thrawn) so she can use her 2nd special to apply armour shred and then calls herself to assist giving her the 3rd. Then Thrawn swaps turns to her, and she applies the 3 stacks to SEE.

Ah I see! Gotcha. Thank you, that's v helpful indeed.

You want thrawn 21 speed slower than armorer (accounting for 20 speed he gets from SEE lead). Then armorer uses this is the way to get her 3rd stack. Thrawn being 1 slower moves right after armorer and uses his tm swap to give armorer another turn where she can give SEE the 3 stacks.

An alternative is to have a DS tank on the team if you have a speedy Thrawn and low gear/speed Armourer.

If you use SEEs link special as the first move the tank will taunt. If they then take damage and drop below 60% health (but don’t die outright) armourer will pick up a third stack of beskar without doing anything. Then on thrawn first turn you can swap to armourer and apply three stacks straightaway to SEE.

Royal Guard tends to be pretty good for this move because he prioritises health and you’ll already have him at r3 for SEE.