Eg. 1 combatant is placed at center, 2 combatants are placed each side of center.
It is eaiser to use pokemon as example. A trainer will have some pokemons, but only 1 or 2 will join the battle and the rest are waiting. Pokemons will be places at different positions in battle scene depending on number.
Basically, if you meet one trainer then it is 1 vs 1. If you meet two then it's 2 vs 2. But there may be other conditions, not only trainer number.
I have checked default battle spot setting, spot of combatant group, spot of battle component and some position node in event, but can't figure out a way to do this.
The battle is in another scene so I can't set game objects in battle scene to the spot of battle component in the field scene.